研究者紹介システム

VAVRICKA Jr John Christopher
ヴァヴリッカ ジュニア ジョン クリストファー
大学院科学技術イノベーション研究科 科学技術イノベーション専攻
准教授
応用化学関係
Last Updated :2022/04/15

研究者情報

所属

  • 【主配置】

    大学院科学技術イノベーション研究科 科学技術イノベーション専攻

学位

  • Ph.D. (Biochemistry), バージニア工科大学

ジャンル

  • 科学・技術 / 生命科学

コメントテーマ

  • 抗ウイルス剤
  • 抗菌剤
  • 抗インフルエンザ薬

研究ニュース

研究活動

研究分野

  • ライフサイエンス / 機能生物化学
  • ライフサイエンス / 生物有機化学
  • ライフサイエンス / 応用生物化学
  • ものづくり技術(機械・電気電子・化学工学) / バイオ機能応用、バイオプロセス工学

受賞

  • 2013年 GENEWIZ, 金唯智论文奖(論文賞)

    VAVRICKA JR, CHRISTOPHER, JOHN

  • 2013年 中科院北京生命科学研究院科研, 论文奖励(論文賞)

    VAVRICKA JR, CHRISTOPHER, JOHN

  • 2013年 Beijing ZEPING Bioscience & Technology Co., Ltd., 荣获2013 年度 泽平优秀论文 奖(優秀論文賞)

    VAVRICKA JR, CHRISTOPHER, JOHN

  • 2013年 Beijing Leadman Biochemistry Co., Ltd., 利德曼杯年度科研成就奖

    VAVRICKA JR, CHRISTOPHER, JOHN

  • 2011年 中国科学院病原微生物与免疫学重点实验室度, 强耀优秀论文奖(優秀論文賞)

    VAVRICKA JR, CHRISTOPHER, JOHN

  • 2011年 中国科学院病原微生物与免疫学重点实验室, 周家炽病毒学论文奖(優秀論文賞)

    VAVRICKA JR, CHRISTOPHER, JOHN

論文

  • Yuichi Kato, Tomoki Oyama, Kentaro Inokuma, Christopher J. Vavricka, Mami Matsuda, Ryota Hidese, Katsuya Satoh, Yutaka Oono, Jo-Shu Chang, Tomohisa Hasunuma, Akihiko Kondo

    AbstractLight/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp. KOR1 was developed through light/dark-conditioned screening. During dark periods with depressed CO2 fixation, KOR1 shows rapid carbohydrate degradation together with increased lipid and carotenoid contents. KOR1 was subsequently characterized with extensive mutation of the ISA1 gene encoding a starch debranching enzyme (DBE). Dynamic time-course profiling and metabolomics reveal dramatic changes in KOR1 metabolism throughout light/dark cycles. During light periods, increased flux from CO2 through glycolytic intermediates is directly observed to accompany enhanced formation of small starch-like particles, which are then efficiently repartitioned in the next dark cycle. This study demonstrates that disruption of DBE can improve biofuel production under light/dark conditions, through accelerated carbohydrate repartitioning into lipid and carotenoid.

    Springer Science and Business Media LLC, 2021年12月, Communications Biology, 4 (1)

    [査読有り]

    研究論文(学術雑誌)

  • Musashi Takenaka, Takanobu Yoshida, Yoshimi Hori, Takahiro Bamba, Masao Mochizuki, Christopher J. Vavricka, Takanari Hattori, Yoshihiro Hayakawa, Tomohisa Hasunuma, Akihiko Kondo

    Elsevier BV, 2021年01月, Talanta, 222, 121625 - 121625, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Naoki Ashida, Kousuke Ida, Yumi Koide, Christopher J. Vavricka, Minoru Izumi, Hiromasa Kiyota

    Thelepamide, an unique ketide-amino acid isolated from a marine annelid wormThelepus crispus, has a unique oxazolidinone ring derived from cysteine, glycine and valine. Rareness in nature as well as promising bioactive possibility make the oxazolidinone ring an attractive synthetic target. The hydroxy oxazolidinone fragment of thelepamide was prepared by acid-catalysedN,O-acetal formation between a ketoamide and formaldehyde. Lactone-carbonyl selective isopropyl addition to an oxazilidine-dione under Grignard conditions also forms the target compound.

    TAYLOR & FRANCIS LTD, 2020年08月, NATURAL PRODUCT RESEARCH, 英語

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    研究論文(学術雑誌)

  • Exploration and Evaluation of Machine Learning-Based Models for Predicting Enzymatic Reactions

    Naoki Watanabe, Masahiro Murata, Teppei Ogawa, Christopher J Vavricka, Akihiko Kondo, Chiaki Ogino, Michihiro Araki

    2020年02月, Journal of Chemical Information and Modeling, 60 (3), 1833 - 1843, 英語

    [査読有り]

  • Christopher J. Vavricka JR, Tatsuma Matsumoto, Hiromasa Kiyota

    Forum: Carbohydrates Coming of Age, 2020年01月, Trends in Glycoscience and Glycotechnology, 32 (185), E1 - E5, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Dynamic metabolomics for engineering biology: Accelerating learning cycles for bioproduction

    Christopher J. Vavricka, Tomohisa Hasunuma, Akihiko Kondo

    2020年01月, Trends in Biotechnology, 38 (1), 68 - 82, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Single-Stage Astaxanthin Production Enhances the Nonmevalonate Pathway and Photosynthetic Central Metabolism in Synechococcus sp. PCC 7002

    Tomohisa Hasunuma, Ayako Takaki, Mami Matsuda, Yuichi Kato, Christopher J. Vavricka, Akihiko Kondo

    2019年10月, ACS Synthetic Biology, 8 (12), 2701 - 2709, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J Vavricka, Takanobu Yoshida, Yuki Kuriya, Shunsuke Takahashi, Teppei Ogawa, Fumie Ono, Kazuko Agari, Hiromasa Kiyota, Jianyong Li, Jun Ishii, Kenji Tsuge, Hiromichi Minami, Michihiro Araki, Tomohisa Hasunuma, Akihiko Kondo

    In the original version of this Article, the abbreviation of 3,4-dihydroxyphenylacetaldehyde synthase presented in the first paragraph of the Discussion section was given incorrectly as DYPAA. The correct abbreviation for this enzyme is DHPAAS. This error has been corrected in both the PDF and HTML versions of the Article.

    2019年05月22日, Nature communications, 10 (1), 2336 - 2336, 英語, 国際誌

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    研究論文(学術雑誌)

  • Christopher J Vavricka, Takanobu Yoshida, Yuki Kuriya, Shunsuke Takahashi, Teppei Ogawa, Fumie Ono, Kazuko Agari, Hiromasa Kiyota, Jianyong Li, Jun Ishii, Kenji Tsuge, Hiromichi Minami, Michihiro Araki, Tomohisa Hasunuma, Akihiko Kondo

    Previous studies have utilized monoamine oxidase (MAO) and L-3,4-dihydroxyphenylalanine decarboxylase (DDC) for microbe-based production of tetrahydropapaveroline (THP), a benzylisoquinoline alkaloid (BIA) precursor to opioid analgesics. In the current study, a phylogenetically distinct Bombyx mori 3,4-dihydroxyphenylacetaldehyde synthase (DHPAAS) is identified to bypass MAO and DDC for direct production of 3,4-dihydroxyphenylacetaldehyde (DHPAA) from L-3,4-dihydroxyphenylalanine (L-DOPA). Structure-based enzyme engineering of DHPAAS results in bifunctional switching between aldehyde synthase and decarboxylase activities. Output of dopamine and DHPAA products is fine-tuned by engineered DHPAAS variants with Phe79Tyr, Tyr80Phe and Asn192His catalytic substitutions. Balance of dopamine and DHPAA products enables improved THP biosynthesis via a symmetrical pathway in Escherichia coli. Rationally engineered insect DHPAAS produces (R,S)-THP in a single enzyme system directly from L-DOPA both in vitro and in vivo, at higher yields than that of the wild-type enzyme. However, DHPAAS-mediated downstream BIA production requires further improvement.

    2019年05月01日, Nature communications, 10 (1), 2015 - 2015, 英語, 国際誌

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    研究論文(学術雑誌)

  • Ryo Ota, Yumi Okamoto, Christopher J.Vavricka, Takuji Oka, Emiko Matsunaga, Kaoru Takegawa, Hiromasa Kiyota, Minoru Izumi

    β-d-Galactofuranose (Galf) is a component of polysaccharides and glycoconjugates. There are few reports about the involvement of galactofuranosyltransferases and galactofuranosidases (Galf-ases) in the synthesis and degradation of galactofuranose-containing glycans. The cell walls of filamentous fungi in the genus Aspergillus include galactofuranose-containing polysaccharides and glycoconjugates, such as O-glycans, N-glycans, and fungal-type galactomannan, which are important for cell wall integrity. In this study, we investigated the synthesis of p-nitrophenyl β-d-galactofuranoside and its disaccharides by chemo-enzymatic methods including use of galactosidase. The key step was selective removal of the concomitant pyranoside by enzymatic hydrolysis to purify p-nitrophenyl β-d-galactofuranoside, a promising substrate for β-d-galactofuranosidase from Streptomyces species.

    2019年02月, Carbohydrate Research, 473, 99 - 103, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Light/dark cycling causes delayed lipid accumulation and increased photoperiod-based biomass yield by altering metabolic flux in oleaginous Chlamydomonas sp.

    Yuichi KATO, Yusuke FUJIHARA, Christopher J. VAVRICKA, Jo-Shu CHANG, Tomohisa HASUMUMA, Akihiko KONDO

    2019年02月, Biotechnology for Biofuels, 12, 39, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Multigram-Scale and Column Chromatography-Free Synthesis of L-Azetidine-2-carboxylic Acid for the Synthesis of Nicotianamine and Its Derivatives

    Tomohiro Takaishi, Kyosuke Wakisaka, Christopher J Vavricka, Hiromasa Kiyota, Minoru Izumi

    2018年12月, Heterocycles, 96 (12), 2126 - 2134, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Tomohisa Hasunuma, Mami Matsuda, Yuichi Kato, Christopher John Vavricka, Akihiko Kondo

    Succinate is a versatile petrochemical compound that can be produced by microorganisms, often from carbohydrate based carbon sources. Phototrophic cyanobacteria including Synechocystis sp. PCC 6803 can more efficiently produce organic acids such as succinate without sugar supplementation, via photosynthetic production of glycogen followed by glycogen utilization, typically under dark conditions. In this study, Synechocystis 6803 bioproduction of organic acids under dark anoxic conditions was found to increase with elevation of temperature from 30 °C to 37 °C. The further enhancement of succinate bioproduction by overexpression of the rate limiting enzyme phosphoenolpyruvate carboxylase resulted in improved glycogen utilization. To gain more insight into the mechanisms underlying the increased organic acid output, a novel temperature dependent metabolomics analysis was performed. Adenylate energy charge was found to decrease along with elevating temperature, while central metabolites glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, glycerol 3-phosphate, malate, fumarate and succinate increased. Temperature dependent 13C-labeling metabolomics analysis further revealed a glycolysis to TCA bottleneck, which could be overcome by addition of CO2, leading to even higher organic acid production. Optimization of initial cell concentration to 25 g-dry cell weight/L, in combination with 100 mM NaHCO3 supplementation, afforded a succinate titer of over 1.8 g/L, the highest reported autotrophic succinate titer. Succinate titers remained high after additional knockout of ackA, resulting in the highest reported autotrophic D-lactate titer as well. The optimization of Synechocystis 6803 organic acid production therefore holds significant promise for CO2 capture and utilization.

    Academic Press Inc., 2018年07月01日, Metabolic Engineering, 48, 109 - 120, 英語

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    研究論文(学術雑誌)

  • Structural insight into the mechanism of neuraminidase inhibitor-resistant mutations in human-infecting H10N8 Influenza A virus

    Babayemi O. Oladejo, Yuhai Bi, Christopher J. Vavricka, Chunrui Li, Yan Chai, Kun Xu, Liqiang Li, Zhe Lu, Jiandong Li, Gary Wong, Sankar Mohan, B. Mario Pinto, Haihai Jiang, Jianxun Qi, George Fu Gao, Po Tien, Yan Wu

    2018年01月, BioRxiv, 378075, 英語

    研究論文(学術雑誌)

  • Synthesis of Halogenated-4-Nitrophenyl 2-deoxy-2-halogeno-pyranosides via N-Halogenosuccinimide Activated Glucal

    Chieri Inoue, Yumi Okamoto, Christopher J. Vavricka, Hiromasa Kiyota, Minoru Izumi

    Reaction of 3,4,6-tri-O-acetyl-a-glucal with silver 4-nitrophenolate in the presence of N-iodosuccinimide and N-bromosuccinimide produced (2,6-dihalo-4-nitro)phenyl 2-halo-2-deoxy-alpha-D-glycopyranosides. Although bromination and iodination of the 4-nitrophenyl group could not be avoided, the resulting (2,6-dihalo-4-nitro)phenylated compounds can be used as substrates or covalent glycosidase inhibitors after deprotection. The stereoselectivity and regioselectivity of the halogenation reactions are described.

    NATURAL PRODUCTS INC, 2018年01月, NATURAL PRODUCT COMMUNICATIONS, 13 (1), 85 - 87, 英語

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    研究論文(学術雑誌)

  • Yuichi Kato, Shih-Hsin Ho, Christopher J. Vavricka, Jo-Shu Chang, Tomohisa Hasunuma, Akihiko Kondo

    The aim of this study was to improve biomass production of the green microalga Chlamydomonas sp. JSC4 under high salinity conditions. For this purpose, heavy ion beam-coupled mutagenesis and evolutionary engineering were performed using JSC4 as the parent strain. After long-term and continuous cultivation with high salinity, salt-resistant strains that grow well even in the presence of 7% sea salt were successfully obtained. Transcriptional analysis revealed inactivation of starch-to-lipid biosynthesis switching, which resulted in delayed starch degradation and decreased lipid content in the salt-resistant strains. Cellular aggregation and hypertrophy during high salinity were relieved in these strains, indicating strong resistance to salt stress. These results suggest that high salinity stress, not the salinity condition itself, is important for activating lipid accumulation mechanisms in microalgae. (C) 2017 Elsevier Ltd. All rights reserved.

    ELSEVIER SCI LTD, 2017年12月, BIORESOURCE TECHNOLOGY, 245 (part B), 1484 - 1490, 英語

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    研究論文(学術雑誌)

  • Yi-Bing Wu, Ya-Zhen Wang, Zhi-Yu Ni, Xia Qing, Qing-Wen Shi, Francoise Sauriol, Christopher J. Vavricka, Yu-Cheng Gu, Hiromasa Kiyota

    Two tetranortriterpenoids with new skeletons, xylomexicanins I and J (1 and 2), were isolated during the investigation of chemical constituents from seeds of the Chinese mangrove, Xylocarpus granatum. Xylomexicanin I (1) is an unprecedented limonoid with bridged B- and C-rings. A biosynthesis pathway for 1 from xylomexicanin F is proposed.

    AMER CHEMICAL SOC, 2017年09月, JOURNAL OF NATURAL PRODUCTS, 80 (9), 2547 - 2550, 英語

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    研究論文(学術雑誌)

  • Christopher J. Vavricka, Chiaki Muto, Tomohisa Hasunuma, Yoshinobu Kimura, Michihiro Araki, Yan Wu, George F. Gao, Hiroshi Ohrui, Minoru Izumi, Hiromasa Kiyota

    The design, synthesis and application of N-acetylneuraminic acid-derived compounds bearing anomeric sulfo functional groups are described. These novel compounds, which we refer to as sulfo-sialic acid analogues, include 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid and its 4-deoxy-3,4-dehydrogenated pseudoglycal. While 2-decarboxy-2-deoxy-2-sulfo-N-acetylneuraminic acid contains no further modifications of the 2-deoxy-pyranose ring, it is still a more potent inhibitor of avian-origin H5N1 neuraminidase (NA) and drug-resistant His275Tyr NA as compared to the oxocarbenium ion transition state analogue 2,3-dehydro-2-deoxy-N-acetylneuraminic acid. The sulfo-sialic acid analogues described in this report are also more potent inhibitors of influenza NA (up to 40-fold) and bacterial NA (up to 8.5-fold) relative to the corresponding anomeric phosphonic acids. These results confirm that this novel anomeric sulfo modification offers great potential to improve the potency of next-generation NA inhibitors including covalent inhibitors.

    NATURE PUBLISHING GROUP, 2017年08月, SCIENTIFIC REPORTS, 7 (1), 8239, 英語

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    研究論文(学術雑誌)

  • Toshihiro Osada, Megumi Maeda, Chinatsu Tanabe, Kaori Furuta, Christopher J. Vavricka, Eiji Sasaki, Mitsuhiro Okano, Yoshinobu Kimura

    Cha o 3 is a newly found glycosylated allergen from Chamaecyparis obtusa (Japanese cypress) pollen. The deduced amino acid sequence of Cha o 3 indicates that this glycoallergen contains a cellulase domain and a number of putative N-glycosylation sites. However, the structures of N-glycans linked to Cha o 3 remain to be determined. In this study, therefore, we analyzed the glycoform of Cha o 3 and found that this glycoallergen carries exclusively plant complex-type N-glycans; major structures were G1cNAc2_ Man(3)Xyl(1)Fuc(1)GlcNAc(2) (39%), GaliFuciGlcNAc(2)Man(3)Xyl(1)FuciGlcNAc(2) (14%), and Gal(2)Fuc(2)G(1)cNAc2Man3. Xyl(1)Fuc(1)GIcNAc(2) (25%). The glycoform of Cha o 3 bearing the Lea epitope is similar to those of Cry j1, Jun a 1, or Cup a 1, major glycoallergens in cedar or cypress pollens, and the predominant occurrence of GIcNAc(2)Man3Xyl(1)Fuc(1)GIcNAc(2) is a common structural feature of glycoallergens from Cupressaceae pollens. (C) 2017 Elsevier Ltd. All rights reserved.

    ELSEVIER SCI LTD, 2017年08月, CARBOHYDRATE RESEARCH, 448, 18 - 23, 英語

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    研究論文(学術雑誌)

  • Chemical and pharmacological research on the plants from genus Ajuga

    QING Xia, YAN Hui-Min, NI Zhi-Yi, VAVRICKA JR Christopher John, ZHANG Man-Li, SHI Qing-Wen, GU Yu-Cheng, KIYOTA Hiromasa

    2017年07月, Heterocyclic Communications, 23 (4), 245, 英語

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    研究論文(学術雑誌)

  • Megumi Maeda, Natsuki Ebara, Misato Tani, Christopher J. Vavricka, Yoshinobu Kimura

    In our previous study, we found unique free N-glycans (FNGs), which carry a single GlcNAc residue (GN1) at the reducing-end side and the Lewis-a epitope at the non-reducing-end side, in the culture broth of rice cells. Based on the FNG structural features and the substrate specificity of plant ENGase, we hypothesized that there might be a novel biosynthetic mechanism responsible for the production of these unique GN1-FNGs, in which high-mannose type (HMT)-GN1-FNGs produced in the cytosol from misfolded glycoproteins by ENGase are transported back into the endoplasmic reticulum and processed to plant complex type (PCT)-GN1-FNGs in the Golgi apparatus. Until now, however, PCT-GN1-FNGs had only been found in the culture broth of rice cultured cells and never in plants, suggesting that the formation of PCT-GN1-FNGs might be generated under special or artificial conditions. In this study, we confirm the presence of PCT-GN1-FNGs, HMT-GN1-FNGs and PCT-GN2-FNGs in the fresh-water plant Egeria densa. These results suggest that a mechanism responsible for the production of PCT-GN1-FNG is present in native plant tissues.

    SPRINGER, 2017年04月, GLYCOCONJUGATE JOURNAL, 34 (2), 229 - 240, 英語

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    研究論文(学術雑誌)

  • Yan Wu, Feng Gao, Jianxun Qi, Yuhai Bi, Lifeng Fu, Sankar Mohan, Yuhang Chen, Xuebing Li, B. Mario Pinto, Christopher J. Vavricka, Po Tien, George F. Gao

    Influenza virus neuraminidase (NA) drug resistance is one of the challenges to preparedness against epidemic and pandemic influenza virus infections. NA N1- and N2-containing influenza viruses are the primary cause of seasonal epidemics and past pandemics. The structural and functional basis underlying drug resistance of the influenza virus N1 NA is well characterized. Yet drug resistance of the N2 strain is not well understood. Here, we confirm that replacement of N2 E119 or I222 results in multidrug resistance, and when the replacements occur together, the sensitivity to NA inhibitors (NAI) is reduced severely. Using crystallographic studies, we showed that E119 replacement results in a loss of hydrogen bonding to oseltamivir and zanamivir, whereas I222 replacement results in a change in the hydrophobic environment that is critical for oseltamivir binding. Moreover, we found that MS-257, a zanamivir-oseltamivir hybrid inhibitor, is less susceptible to drug resistance. The binding mode of MS-257 shows that increased hydrogen bonding interactions between the inhibitor and NA active site anchor the inhibitor within the active site and allow adjustments in response to active-site modifications. Such stability is likely responsible for the observed reduced susceptibility to drug resistance. MS-257 serves as a next-generation anti-influenza virus drug candidate and serves also as a scaffold for further design of NAIs. IMPORTANCE Oseltamivir and zanamivir are the two major antiviral drugs available for the treatment of influenza virus infections. However, multidrug-resistant viruses have emerged in clinical cases, which pose a challenge for the development of new drugs. N1 and N2 subtypes exist in the viruses which cause seasonal epidemics and past pandemics. Although N1 drug resistance is well characterized, the molecular mechanisms underlying N2 drug resistance are unknown. A previous report showed that an N2 E119V/I222L dual mutant conferred drug resistance to seasonal influenza virus. Here, we confirm that these substitutions result in multidrug resistance and dramatically reduced sensitivity to NAI. We further elucidate the molecular mechanism underlying N2 drug resistance by solving crystal structures of the N2 E119V and I222L mutants and the dual mutant. Most importantly, we found that a novel oseltamivir-zanamivir hybrid inhibitor, MS-257, remains more effective against drug-resistant N2 and is a promising candidate as a next-generation anti-influenza virus drug.

    AMER SOC MICROBIOLOGY, 2016年12月, JOURNAL OF VIROLOGY, 90 (23), 10693 - 10700, 英語

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    研究論文(学術雑誌)

  • Megumi Maeda, Misato Tani, Takeo Yoshiie, Christopher J. Vavricka, Yoshinobu Kimura

    The Japanese cedar pollen allergen (Cry j1) and the mountain cedar pollen allergen (Jun a1) are glycosylated with plant complex type N-glycans bearing Lewis a epitope(s) (Gal beta 1-3[Fuc alpha 1-4]GlcNAc-). The biological significance of Lewis a type plant N-glycans and their effects on the human immune system remain to be elucidated. Since a substantial amount of such plant specific N-glycans are required to evaluate immunological activity, we have searched for good plant-glycan sources to characterize Lewis a epitope-containing plant N-glycans. In this study, we have found that three water plants, Elodea nuttallii, Egeria densa, and Ceratophyllum demersum, produce glycoproteins bearing Lewis a units. Structural analysis of the N-glycans revealed that almost all glycoproteins expressed in these three water plants predominantly carry plant complex type N-glycans including the Lewis a type, suggesting that these water plants are good sources for preparation of Lewis a type plant N-glycans in substantial amounts. (C) 2016 Elsevier Ltd. All rights reserved.

    ELSEVIER SCI LTD, 2016年11月, CARBOHYDRATE RESEARCH, 435, 50 - 57, 英語

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    研究論文(学術雑誌)

  • Ying Wu, Christopher J. Vavricka, Yan Wu, Qing Li, Santosh Rudrawar, Robin J. Thomson, Mark von Itzstein, George F. Gao, Jianxun Qi

    HIGHER EDUCATION PRESS, 2015年10月, PROTEIN & CELL, 6 (10), 771 - 773, 英語

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    研究論文(学術雑誌)

  • Xiaoman Sun, Qing Li, Yan Wu, Mingyang Wang, Yue Liu, Jianxun Qi, Christopher J. Vavricka, George F. Gao

    There are nine subtypes of influenza A virus neuraminidase (NA), N1 to N9. In addition, influenza B virus also contains NA, and there are two influenza virus NA-like molecules, N10 and N11, which were recently identified from bats. Crystal structures for all of these proteins have been solved, with the exception of N7, and there is no published report of N6, although a structure has been deposited in the Protein Data Bank. Here, we present the N7 and N6 structures at 2.1 angstrom and 1.8 angstrom, respectively. Structural comparison of all NA subtypes shows that both N7 and N6 highly resemble typical group 2 NA structures with some special characteristics, including an additional cavity adjacent to their active sites formed by novel 340-loop conformations. Comparative analysis also revealed new structural insights into the N-glycosylation, calcium binding, and second sialic acid binding site of influenza virus NA. This comprehensive study is critical for understanding the complexity of the most successful influenza drug target and for the structure-based design of novel influenza inhibitors.

    AMER SOC MICROBIOLOGY, 2014年08月, JOURNAL OF VIROLOGY, 88 (16), 9197 - 9207, 英語

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    研究論文(学術雑誌)

  • Wael M. Abdel-Mageed, Soad A. H. Bayoumi, Caixia Chen, Christopher J. Vavricka, Li Li, Ajamaluddin Malik, Huanqin Dai, Fuhang Song, Luoqiang Wang, Jingyu Zhang, George F. Gao, Yali Lv, Lihong Liu, Xueting Liu, Hanaa M. Sayed, Lixin Zhang

    The high mutation rate of RNA viruses has resulted in limitation of vaccine effectiveness and increased emergence of drug-resistant viruses. New effective antivirals are therefore needed to control of the highly mutative RNA viruses. The n-butanol fraction of the stem bark of Mangifera indica exhibited inhibitory activity against influenza neuraminidase (NA) and coxsackie virus 3C protease. Bioassay guided phytochemical study of M. indica stem bark afforded two new compounds including one benzophenone C-glycoside (4) and one xanthone dimer (7), together with eleven known compounds. The structures of these isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Anti-influenza and anti-coxsackie virus activities were evaluated by determining the inhibition of anti-influenza neuraminidase (NA) from pandemic A/RI/5+/1957 H2N2 influenza A virus and inhibition of coxsackie B3 virus 3C protease, respectively. The highest anti-influenza activity was observed for compounds 8 and 9 with IC50 values of 11.9 and 9.2 mu M, respectively. Compounds 8 and 9 were even more potent against coxsackie B3 virus 3C protease, with IC50 values of 1.1 and 2.0 mu M, respectively. Compounds 8 and 9 showed weak cytotoxic effect against human hepatocellular carcinoma and human epithelial carcinoma cell lines through MTT assay. (C) 2014 Elsevier Ltd. All rights reserved.

    PERGAMON-ELSEVIER SCIENCE LTD, 2014年04月, BIOORGANIC & MEDICINAL CHEMISTRY, 22 (7), 2236 - 2243, 英語

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    研究論文(学術雑誌)

  • Christopher John Vavricka, Qian Han, Prajwalini Mehere, Haizhen Ding, Bruce M. Christensen, Jianyong Li

    Differences in the metabolism of tyrosine between insects and mammals present an interesting example of molecular evolution. Both insects and mammals possess fine-tuned systems of enzymes to meet their specific demands for tyrosine metabolites; however, more homologous enzymes involved in tyrosine metabolism have emerged in many insect species. Without knowledge of modern genomics, one might suppose that mammals, which are generally more complex than insects and require tyrosine as a precursor for important catecholamine neurotransmitters and for melanin, should possess more enzymes to control tyrosine metabolism. Therefore, the question of why insects actually possess more tyrosine metabolic enzymes is quite interesting. It has long been known that insects rely heavily on tyrosine metabolism for cuticle hardening and for innate immune responses, and these evolutionary constraints are likely the key answers to this question. In terms of melanogenesis, mammals also possess a high level of regulation; yet mammalian systems possess more mechanisms for detoxification whereas insects accelerate pathways like melanogenesis and therefore must bear increased oxidative pressure. Our research group has had the opportunity to characterize the structure and function of many key proteins involved in tyrosine metabolism from both insects and mammals. In this mini review we will give a brief overview of our research on tyrosine metabolic enzymes in the scope of an evolutionary perspective of mammals in comparison to insects.

    WILEY, 2014年02月, INSECT SCIENCE, 21 (1), 13 - 19, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Characterization of two distinct neuraminidases from avian-origin human-infecting H7N9 influenza viruses

    WU Yan, BI Yuhai, VAVRICKA JR Christopher John, SUN Xiaoman, ZHANG Yanfang, GAO Feng, ZHAO Min, XIAO Haixia, QIN Chengfeng, HE Jianhua, LIU Wenjun, YAN Jinghua, QI Jianxun, GAO George F

    2013年10月, Cell Research, 23, 1347 - 1355, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Qing Li, Jianxun Qi, Yan Wu, Hiromasa Kiyota, Kosuke Tanaka, Yoshitomo Suhara, Hiroshi Ohrui, Yasuo Suzuki, Christopher J. Vavricka, George F. Gao

    The influenza virus neuraminidase H274Y substitution is a highly prevalent amino acid substitution associated with resistance to the most heavily used influenza drug, oseltamivir. Previous structural studies suggest that the group specific 252 residue ( Y252 in group 1 and T252 in group 2) might be a key factor underlying H274Y resistance. However, H274Y has only been reported in N1 subtypes, which indicates that there must be additional key residues that determine H274Y resistance. Furthermore, we found that members of NA serotype N3 also possess Y252, raising the key question as to whether or not H274Y resistance may also be possible for some group 2 NAs. Here, we demonstrate that the H274Y substitution results in mild oseltamivir resistance for N3. Comparative structural analysis of N3, N1, and their 274Y variants indicates that the interaction of residue 296 ( H in N1 and nonaromatic for other serotypes) with conserved W295 is another important determinant of oseltamivir resistance.

    AMER SOC MICROBIOLOGY, 2013年09月, JOURNAL OF VIROLOGY, 87 (18), 10016 - 10024, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Yan Wu, Guangrong Qin, Feng Gao, Yue Liu, Christopher J. Vavricka, Jianxun Qi, Hualiang Jiang, Kunqian Yu, George F. Gao

    The recently discovered 150-cavity (formed by loop residues 147-152, N2 numbering) adjacent to the enzymatic active site of group 1 influenza A neuraminidase (NA) has introduced a novel target for the design of next-generation NA inhibitors. However, only group 1 NAs, with the exception of the 2009 pandemic H1N1 NA, possess a 150-cavity, and no 150-cavity has been observed in group 2 NAs. The role of the 150-cavity played in enzymatic activity and inhibitor binding is not well understood. Here, we demonstrate for the first time that oseltamivir carboxylate can induce opening of the rigid closed N2 150-loop and provide a novel mechanism for 150-loop movement using molecular dynamics simulations. Our results provide the structural and biophysical basis of the open form of 150-loop and illustrates that the inherent flexibility and the ligand induced flexibility of the 150-loop should be taken into consideration for future drug design.

    NATURE PUBLISHING GROUP, 2013年03月, SCIENTIFIC REPORTS, 3, 1551, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka, Yue Liu, Hiromasa Kiyota, Nongluk Sriwilaijaroen, Jianxun Qi, Kosuke Tanaka, Yan Wu, Qing Li, Yan Li, Jinghua Yan, Yasuo Suzuki, George F. Gao

    Development of novel influenza neuraminidase inhibitors is critical for preparedness against influenza outbreaks. Knowledge of the neuraminidase enzymatic mechanism and transition-state analogue, 2-deoxy-2,3-didehydro-N-acetylneuraminic acid, contributed to the development of the first generation anti-neuraminidase drugs, zanamivir and oseltamivir. However, lack of evidence regarding influenza neuraminidase key catalytic residues has limited strategies for novel neuraminidase inhibitor design. Here, we confirm that influenza neuraminidase conserved Tyr406 is the key catalytic residue that may function as a nucleophile; thus, mechanism-based covalent inhibition of influenza neuraminidase was conceived. Crystallographic studies reveal that 2 alpha, 3ax-difluoro-N-acetylneuraminic acid forms a covalent bond with influenza neuraminidase Tyr406 and the compound was found to possess potent anti-influenza activity against both influenza A and B viruses. Our results address many unanswered questions about the influenza neuraminidase catalytic mechanism and demonstrate that covalent inhibition of influenza neuraminidase is a promising and novel strategy for the development of next-generation influenza drugs.

    NATURE PUBLISHING GROUP, 2013年02月, NATURE COMMUNICATIONS, 4, 1491, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Qing Li, Xiaoman Sun, Zhixin Li, Yue Liu, Christopher J. Vavricka, Jianxun Qi, George F. Gao

    The recent discovery of the unique genome of influenza virus H17N10 in bats raises considerable doubt about the origin and evolution of influenza A viruses. It also identifies a neuraminidase (NA)-like protein, N10, that is highly divergent from the nine other well-established serotypes of influenza A NA(N1-N9). The structural elucidation and functional characterization of influenza NAs have illustrated the complexity of NA structures, thus raising a key question as to whether N10 has a special structure and function. Here the crystal structure of N10, derived from influenza virus A/little yellow-shouldered bat/Guatemala/153/2009 (H17N10), was solved at a resolution of 2.20 angstrom. Overall, the structure of N10 was found to be similar to that of the other known influenza NA structures. In vitro enzymatic assays demonstrated that N10 lacks canonical NA activity. A detailed structural analysis revealed dramatic alterations of the conserved active site residues that are unfavorable for the binding and cleavage of terminally linked sialic acid receptors. Furthermore, an unusual 150-loop (residues 147-152) was observed to participate in the intermolecular polar interactions between adjacent N10 molecules of the N10 tetramer. Our study of influenza N10 provides insight into the structure and function of the sialidase superfamily and sheds light on the molecular mechanism of bat influenza virus infection.

    NATL ACAD SCIENCES, 2012年11月, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 109 (46), 18897 - 18902, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka, Qing Li, Yan Wu, Jianxun Qi, Mingyang Wang, Yue Liu, Feng Gao, Jun Liu, Enguang Feng, Jianhua He, Jinfang Wang, Hong Liu, Hualiang Jiang, George F. Gao

    The 2009 H1N1 influenza pandemic (pH1N1) led to record sales of neuraminidase (NA) inhibitors, which has contributed significantly to the recent increase in oseltamivir-resistant viruses. Therefore, development and careful evaluation of novel NA inhibitors is of great interest. Recently, a highly potent NA inhibitor, laninamivir, has been approved for use in Japan. Laninamivir is effective using a single inhaled dose via its octanoate prodrug (CS-8958) and has been demonstrated to be effective against oseltamivir-resistant NA in vitro. However, effectiveness of laninamivir octanoate prodrug against oseltamivir-resistant influenza infection in adults has not been demonstrated. NA is classified into 2 groups based upon phylogenetic analysis and it is becoming clear that each group has some distinct structural features. Recently, we found that pH1N1 N1 NA (p09N1) is an atypical group 1 NA with some group 2-like features in its active site (lack of a 150-cavity). Furthermore, it has been reported that certain oseltamivir-resistant substitutions in the NA active site are group 1 specific. In order to comprehensively evaluate the effectiveness of laninamivir, we utilized recombinant N5 (typical group 1), p09N1 (atypical group 1) and N2 from the 1957 pandemic H2N2 (p57N2) (typical group 2) to carry out in vitro inhibition assays. We found that laninamivir and its octanoate prodrug display group specific preferences to different influenza NAs and provide the structural basis of their specific action based upon their novel complex crystal structures. Our results indicate that laninamivir and zanamivir are more effective against group 1 NA with a 150-cavity than group 2 NA with no 150-cavity. Furthermore, we have found that the laninamivir octanoate prodrug has a unique binding mode in p09N1 that is different from that of group 2 p57N2, but with some similarities to NA-oseltamivir binding, which provides additional insight into group specific differences of oseltamivir binding and resistance.

    PUBLIC LIBRARY SCIENCE, 2011年10月, PLOS PATHOGENS, 7 (10), e1002249, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Mingyang Wang, Jianxun Qi, Yue Liu, Christopher J. Vavricka, Yan Wu, Qing Li, George F. Gao

    There are 9 serotypes of neuraminidase (NA) from influenza A virus (N1 to N9), which are classified into two groups based on primary sequences (groups 1 and 2). The structural hallmark of the two groups is the presence or absence of an extra 150-cavity (formed by the 150-loop) in the active site. Thus far, structures of NAs from 6 out of the 9 serotypes have been solved. Here, we solved the N5 structure, the last unknown structure group 1 serotype with a unique Asn147 residue in its 150-loop, demonstrating that it has an extended 150-cavity that closes upon inhibitor binding.

    AMER SOC MICROBIOLOGY, 2011年08月, JOURNAL OF VIROLOGY, 85 (16), 8431 - 8435, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka

    HIGHER EDUCATION PRESS, 2011年08月, PROTEIN & CELL, 2 (8), 601 - 603, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher John Vavricka, Liu Yue, Li Qing, Shi Yi, Wu Yan, Sun YePing, Qi JianXun, George Fu Gao

    Since the 2009 pandemic H1N1 swine-origin influenza A virus (09 S-OIV) has reminded the world about the global threat of the ever changing influenza virus, many questions regarding the detailed re-assortment of influenza viruses yet remain unanswered. Influenza A virus is the causative agent of the pandemic flu and contains 2 major antigenic glycoproteins on its surface: (i) hemagglutinin (HA); and (ii) neuraminidase (NA). The structures of the 09 S-OIV HA and NA proteins (09H1 and 09N1) have recently been resolved in our laboratory and provide some clues as to why the 09 S-OIV re-assortment virus is highly infectious with severe consequences in humans. For example, the 09H1 is highly similar to the HA of the 1918 influenza A pandemic virus in overall structure and especially in regards to its 5 defined antibody binding epitopes. For 09N1, its most distinctive feature is the lack of a 150-loop active site cavity, which was previously predicted to be present in all N1 NAs, and we hypothesize that the 150-loop may play a important role in the substrate specificity (alpha 2,3 or alpha 2,6 linked sialic acid receptors) and enzymatic mechanism of influenza NA. Combination of the HA and NA with special characteristics for the 09 S-OIV might contribute to its high increased transmissibility in humans.

    SCIENCE CHINA PRESS, 2011年06月, CHINESE SCIENCE BULLETIN, 56 (17), 1747 - 1752, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Mingwei Sun, Christopher J. Vavricka, Baoli Zhu

    HIGHER EDUCATION PRESS, 2011年04月, PROTEIN & CELL, 2 (4), 261 - 263, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher Vavricka, Qian Han, Yongping Huang, Sara M. Erickson, Kim Harich, Bruce M. Christensen, Jianyong Li

    One protein in Aedes aegypti, classified into the aromatic amino acid decarboxylase (AAAD) family based on extremely high sequence homology (similar to 70%) with dopa decarboxylase (Ddc), was biochemically investigated. Our data revealed that this predicted AAAD protein use L-dopa as a substrate, as does Ddc, but it catalyzes the production of 3,4-dihydroxylphenylacetaldehyde (DHPAA) directly from L-dopa and apparently has nothing to do with the production of any aromatic amine. The protein is therefore named DHPAA synthase. This subsequently led to the identification of the same enzyme in Drosophila melanogaster, Anopheles gambiae and Culex quinquefasciatus by an initial prediction of putative DHPAA synthase based on sequence homology and subsequent verification of DHPAA synthase identity through protein expression and activity assays. DHPAA is highly toxic because its aldehyde group readily reacts with the primary amino groups of proteins, leading to protein crosslinking and inactivation. It has previously been demonstrated by several research groups that Drosophila DHPAA synthase was expressed in tissues that produce cuticle materials and apparent defects in regions of colorless, flexible cuticular structures have been observed in its gene mutants. The presence of free amino groups in proteins, the high reactivity of DHPAA with the free amino groups, and the genetically ascertained function of the Drosophila DHPAA synthase in the formation of colorless, flexible cuticle, when taken together, suggest that mosquito and Drosophila DHPAA synthases are involved in the formation of flexible cuticle through their reactive DHPAA-mediated protein crosslinking reactions. Our data illustrate how a seemingly highly toxic pathway can serve for an important physiological function in insects.

    PUBLIC LIBRARY SCIENCE, 2011年01月, PLOS ONE, 6 (1), e16124, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Prajwalini Mehere, Qian Han, Justin A. Lemkul, Christopher J. Vavricka, Howard Robinson, David R. Bevan, Jianyong Li

    Tyrosine aminotransferase (TAT) catalyzes the transamination of tyrosine and other aromatic amino acids. The enzyme is thought to play a role in tyrosinemia type II, hepatitis and hepatic carcinoma recovery. The objective of this study is to investigate its biochemical and structural characteristics and substrate specificity in order to provide insight regarding its involvement in these diseases. Mouse TAT (mTAT) was cloned from a mouse cDNA library, and its recombinant protein was produced using Escherichia coli cells and purified using various chromatographic techniques. The recombinant mTAT is able to catalyze the transamination of tyrosine using a-ketoglutaric acid as an amino group acceptor at neutral pH. The enzyme also can use glutamate and phenylalanine as amino group donors and p-hydroxyphenylpyruvate, phenylpyruvate and alpha-ketocaproic acid as amino group acceptors. Through macromolecular crystallography we have determined the mTAT crystal structure at 2.9 angstrom resolution. The crystal structure revealed the interaction between the pyridoxal-5'-phosphate cofactor and the enzyme, as well as the formation of a disulphide bond. The detection of disulphide bond provides some rational explanation regarding previously observed TAT inactivation under oxidative conditions and reactivation of the inactive TAT in the presence of a reducing agent. Molecular dynamics simulations using the crystal structures of Trypanosoma cruzi TAT and human TAT provided further insight regarding the substrate-enzyme interactions and substrate specificity. The biochemical and structural properties of TAT and the binding of its cofactor and the substrate may help in elucidation of the mechanism of TAT inhibition and activation.

    HIGHER EDUCATION PRESS, 2010年11月, PROTEIN & CELL, 1 (11), 1023 - 1032, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Novel immunodominant peptide presentation strategy: a featured HLA-A*2402 restricted CTL-epitope stabilized by intra-chain hydrogen-bonds from SARS-CoV nucleocapsid protein

    LIU Jun, WU Peng, GAO Feng, QI Jianxun, KAWANA-TACHIKAWA Ai, XIE Jing, VAVRICKA JR Christopher John, IWAMOTO Aikichi, LI Taisheng, GAO George F

    2010年11月, Journal of Virology, 84, 11849 - 11857, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Qing Li, Jianxun Qi, Wei Zhang, Christopher J. Vavricka, Yi Shi, Jinhua Wei, Enguang Feng, Jingshan Shen, Jilong Chen, Di Liu, Jianhua He, Jinghua Yan, Hong Liu, Hualiang Jiang, Maikun Teng, Xuebing Li, George F. Gao

    Influenza A virus neuraminidase can be classified into groups 1 and 2 on the basis of its primary structure. The main structural feature of group 1 neuraminidase is an extra cavity in the active site, the 150-cavity. Here we present the crystal structure of neuraminidase from the 2009 pandemic H1N1 influenza strain. In contrast to other characterized N1 neuraminidases, which are all members of group 1, 2009 H1N1 neuraminidase does not have a 150-cavity.

    NATURE PUBLISHING GROUP, 2010年10月, NATURE STRUCTURAL & MOLECULAR BIOLOGY, 17 (10), 1266 - 1268, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka, Bruce M. Christensen, Jianyong Li

    Eumelanin is a heteropolymer that is generally composed of hydroxylated indole residues and plays diverse protective functions in various species. Melanin is derived from the amino acid tyrosine and production of melanin is a highly complex oxidative process with a number of steps that can either proceed enzymatically or non-enzymatically. Although melanin plays important protective roles in many species, during melanization, particularly in steps that can proceed non-enzymatically, many toxic intermediates are produced, including semi-quinones, dopaquinone, indole-quinones and moreover, the production of many reactive oxygen species. To mitigate the production of reactive species, a number of proteins that regulate the biochemical process of melanization have evolved in various living species, which is closely related to adaptation and physiological requirements. In this communication, we discuss differences between non-enzymatic and enzymatic processes of melanization and the enzymatic regulation of melanization in difference species with an emphasis on differences between mammals and insects. Comparison between melanization and insect sclerotization is also emphasized which raises some interesting questions about the current models of these pathways.

    HIGHER EDUCATION PRESS, 2010年09月, PROTEIN & CELL, 1 (9), 830 - 841, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Sun YePing, Shi Yi, Zhang Wei, Li Qing, Liu Di, Christopher Vavricka, Yan JingHua, George F. Gao

    The 2009 swine-origin influenza virus (S-OIV, H1N1 subtype) has developed into a new pandemic influenza as announced by the World Health Organization. In order to uncover clues about the determinants for virulence and pathogenicity of the virus, we characterized the functional modules of the surface glycoprotein hemagglutinin (HA), the most important protein in molecular epidemiology and pathogenesis of influenza viruses. We analyzed receptor binding sites, basic patch, neutralization antibody epitopes and T cell epitopes in the HA protein of the current S-OIV according to the corresponding functional and structural modules previously characterized in other H1 HA molecules or HA molecules of other subtypes. We compared their differences and similarities systematically. Based on the amino acids defined as the functional and structural modules, the HA protein of 2009 S-OIV should specifically bind to the human 2,6-receptor. The D225G/E mutation in HA, which is found in some isolates, may confer dual binding specificity to the 2,3- and 2,6-receptor based on previously reported work. This HA variant contains two basic patches, one of which results in increased basicity, suggesting enhanced membrane fusion function. The 2009 S-OIV HA also has an extra glycosylation site at position 276. Four of the five antibody neutralization epitopes identified in A/RP/8/34(H1N1) were exposed, but the other was hidden by a glycosylation site. The previously identified cytotoxic T cell epitopes in various HA molecules were summarized and their corresponding sequences in 2009 S-OIV HA were defined. These results are critical for understanding the pathogenicity of the virus and host immune response against the virus.

    SCIENCE PRESS, 2010年06月, SCIENCE CHINA-LIFE SCIENCES, 53 (6), 633 - 642, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Wei Zhang, Jianxun Qi, Yi Shi, Qing Li, Feng Gao, Yeping Sun, Xishan Lu, Qiong Lu, Christopher J. Vavricka, Di Liu, Jinghua Yan, George F. Gao

    Influenza virus is the causative agent of the seasonal and occasional pandemic flu. The current H1N1 influenza pandemic, announced by the WHO in June 2009, is highly contagious and responsible for global economic losses and fatalities. Although the H1N1 gene segments have three origins in terms of host species, the virus has been named swine-origin influenza virus (S-OIV) due to a predominant swine origin. 2009 S-OIV has been shown to highly resemble the 1918 pandemic virus in many aspects. Hemagglutinin is responsible for the host range and receptor binding of the virus and is therefore a primary indicator for the potential of infection. Primary sequence analysis of the 2009 S-OIV hemagglutinin (HA) reveals its closest relationship to that of the 1918 pandemic influenza virus, however, analysis at the structural level is necessary to critically assess the functional significance. In this report, we report the crystal structure of soluble hemagglutinin H1 (09H1) at 2.9 angstrom, illustrating that the 09H1 is very similar to the 1918 pandemic HA (18H1) in overall structure and the structural modules, including the five defined antiboby (Ab)-binding epitopes. Our results provide an explanation as to why sera from the survivors of the 1918 pandemics can neutralize the 2009 S-OIV, and people born around the 1918 are resistant to the current pandemic, yet younger generations are more susceptible to the 2009 pandemic.

    HIGHER EDUCATION PRESS, 2010年05月, PROTEIN & CELL, 1 (5), 459 - 467, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka, Keith W. Ray, Bruce M. Christensen, Jianyong Li

    Dopachrome tautomerase (DCT) plays a critical role in lowering the oxidative stress resulting from melanogenesis. Levels of DCT are elevated in melanoma cell lines that are especially resistant to chemotherapy and radiation. DCT is processed as a melanoma antigen and is a potential target for immunotherapy. In order to establish a more complete understanding of the role that DCT may play in the etiology and treatment of melanoma skin cancer, isolation of highly pure and properly processed protein is necessary. Purification of native DCT has been problematic due to a hydrophobic transmembrane anchor and interactions with melanin. In this study, DCT was expressed, without its carboxy-terminal transmembrane region using an Sf9 insect cell protein expression system and its recombinant protein was purified by various chromatographic techniques. Analysis of DCT tryptic peptides by MALDI-TOF/TOF determined N-glycosylation as a primary post-translational modification. Our success in the expression of soluble mammalian DCT and the characterization of N-glycosylation sites is a useful reference toward the comprehensive understanding of the structure/function relationship of mammalian DCT.

    SPRINGER, 2010年04月, PROTEIN JOURNAL, 29 (3), 204 - 212, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Junsuo S. Li, Christopher J. Vavricka, Bruce M. Christensen, Jianyong Li

    yA novel dopachrome conversion enzyme (DCE) is present in insects and involved in their melanization pathway. DCE shares no sequence homology with any noninsect species from bacteria to humans. Several DCE sequences have been available, but enzyme structure and catalytic mechanism are unclear. This study concerns DCE PTMs, especially glycosylation. A mosquito DCE was purified and its monosaccharide composition, N-glycosylation site, and oligosaccharide structures were determined. Results showed that N-acetyl D-glucosamine and D-mannose are the major monosaccharides and L-fucose, D-xylose, and D-arabinose are the minor ones in mosquito DCE. Glycosylation site and oligosaccharide structures were elucidated from MS and MS/MS spectra of trypsin-digested DCE glycopeptides. A single N-glycosylation site (Asn(285)-Glu-Thr) was identified in DCE and was proven to be fully glycosylated. Man(3)GlcNAC(2), Man(3)(Fuc)(1-2)GlcNAc(2), and their truncated structures were the dominant oligosaccharides. In addition, high mannose-type structures (Man(4-7)(Fuc)GlcNAc(2)) were also identified. Removal of DCE N-oligosaccharides with peptide N-glycosidase (PNGase F) decreased its activity and thermal stability. However, partial DCE deglycosylation with alpha-mannosidase or alpha-fucosidase somewhat stimulated its activity and improved its thermal stability. During mass spectrometric analysis of DCE glycopeptides, their CID patterns were highly intriguing, in that some glycopeptides underwent both C-terminal rearrangement and formation of dimeric structures during CID. Results of this study provide an interesting example in terms of potential complexity of the glycopeptide CID fragmentation pattern.

    WILEY-V C H VERLAG GMBH, 2007年08月, PROTEOMICS, 7 (15), 2557 - 2569, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Christopher J. Vavricka, Shunsuke Takahashi, Naoki Watanabe, Musashi Takenaka, Mami Matsuda, Takanobu Yoshida, Ryo Suzuki, Hiromasa Kiyota, Jianyong Li, Hiromichi Minami, Jun Ishii, Kenji Tsuge, Michihiro Araki, Akihiko Kondo, Tomohisa Hasunuma

    Abstract Engineering the microbial production of secondary metabolites is limited by the known reactions of correctly annotated enzymes. Therefore, the machine learning discovery of specialized enzymes offers great potential to expand the range of biosynthesis pathways. Benzylisoquinoline alkaloid production is a model example of metabolic engineering with potential to revolutionize the paradigm of sustainable biomanufacturing. Existing bacterial studies utilize a norlaudanosoline pathway, whereas plants contain a more stable norcoclaurine pathway, which is exploited in yeast. However, committed aromatic precursors are still produced using microbial enzymes that remain elusive in plants, and additional downstream missing links remain hidden within highly duplicated plant gene families. In the current study, machine learning is applied to predict and select plant missing link enzymes from homologous candidate sequences. Metabolomics-based characterization of the selected sequences reveals potential aromatic acetaldehyde synthases and phenylpyruvate decarboxylases in reconstructed plant gene-only benzylisoquinoline alkaloid pathways from tyrosine. Synergistic application of the aryl acetaldehyde producing enzymes results in enhanced benzylisoquinoline alkaloid production through hybrid norcoclaurine and norlaudanosoline pathways.

    Springer Science and Business Media LLC, 2022年12月, Nature Communications, 13 (1), 1405, 英語

    研究論文(学術雑誌)

MISC

  • 新たに設計した代謝経路を用いた大腸菌によるアルカロイド高生産

    蓮沼 誠久, Christopher John Vavricka Jr., 荒木通啓

    2020年01月, バイオサイエンスとインダストリー, 78 (1), 32 - 33, 日本語

    記事・総説・解説・論説等(学術雑誌)

  • シアリダーゼ阻害剤・抗インフルエンザ薬の創出 - スルホシアル酸の展開

    清田洋正, C. J. Vavricka

    2018年05月, 化学, 73 (5), 66 - 67, 日本語

    記事・総説・解説・論説等(学術雑誌)

  • George F. Gao, Christopher J. Vavricka

    ELSEVIER SCIENCE BV, 2011年05月, ANTIVIRAL RESEARCH, 90 (2), A26 - A26, 英語

    研究発表ペーパー・要旨(国際会議)

講演・口頭発表等

  • Genome-scale prediction of gene ontology from yeast knockout MASS fingerprints

    VAVRICKA, CHRISTOPHER JOHN

    Frontiers in Genome Engineering 2019, 2019年11月25日, 英語, 国際会議

    ポスター発表

  • Application of the design, build, test and learn paradigm to the discovery and engineering of specialized aromatic aldehyde synthases

    VAVRICKA, CHRISTOPHER JOHN, 清田洋正, 荒木通啓, 近藤昭彦, 蓮沼誠久

    The 37th Symposium on Environmental Science of Pesticide, 2019年11月21日, 英語

    ポスター発表

  • Re-design, synthesis, and bio-analysis of sulfosialic acids as covalent inhibitors of neuraminidase

    VAVRICKA, CHRISTOPHER JOHN, 松本 達磨, 荒木 通啓, 蓮沼 誠久, 泉 実, 清田 洋正

    第61回天然有機化合物討論会, 2019年09月, 英語, 国内会議

    ポスター発表

  • A ‘DBTL’ workflow for engineering enzymes in the reticuline pathway

    VAVRICKA, CHRISTOPHER JOHN

    iBioN 2018, 2018年11月, 英語, Nanjig Tech University, 国際会議

    口頭発表(一般)

  • Discovery and improvement of covalent influenza neuraminidase inhibitors

    VAVRICKA, CHRISTOPHER JOHN

    250th American Chemical Society National Meeting & Exposition, 2015年, 英語

    口頭発表(一般)

  • Influenza neuraminidase: diversity in structure (and function?)

    VAVRICKA, CHRISTOPHER JOHN, GEORGE F. GAO

    2nd Antivirals Congress, 英語

    口頭発表(一般)

  • Structural and functional analysis of laninamivir and its octonoate prodrug reveals group specific mechanisms of influenza NA inhibition

    VAVRICKA, CHRISTOPHER JOHN, GEORGE F. GAO

    24th International Conference on Antiviral Research, 英語

    口頭発表(一般)

  • 2009 pandemic influenza: special features of HA and NA influenza surface proteins

    VAVRICKA, CHRISTOPHER JOHN, GEORGE F. GAO

    8th China-Japan International Conference of Virology, 英語

    口頭発表(一般)

共同研究・競争的資金等の研究課題

  • ヴァヴリッカ クリストファー

    学術研究助成基金助成金/基盤研究(C), 2018年04月 - 2021年03月

    競争的資金

  • 新規抗インフルエンザ薬:不可逆的シアリダーゼ阻害剤の創出(スルホシ アル酸の展開)

    バブリッカ クリストファー

    加藤記念財団, 研究助成, 神戸大学, 大学院科学技術イノベーション研究科, 2018年 - 2018年

産業財産権

  • ベンジルイソキノリンアルカロイド(BIA)産生用の組換え宿主細胞及びベンジルイソキノリンアルカロイド(BIA)の新規製造方法

    クリストファー ジョン ヴァヴリッカ ジュニア, 蓮沼 誠久, 荒木 通啓, 近藤 昭彦

    特願2018-203904, 2018年

    特許権

  • シアル酸誘導体、その製造方法及びそれを利用したシアリダーゼ阻害剤、抗菌剤、抗ウイルス剤

    クリストファー ジョン ヴァヴリッカ ジュニア, 清田洋正

    特願2016-162979, 2016年

    特許権