1
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Wang L, Wu Y, Hu J, Yin D, Wei W, Wen J, Chen X, Gao C, Zhou Y, Liu J, Hu G, Li X, Wu J, Zhou Z, Liu L, Song W. Unlocking the function promiscuity of old yellow enzyme to catalyze asymmetric Morita-Baylis-Hillman reaction. Nat Commun 2024; 15:5737. [PMID: 38982157 PMCID: PMC11233575 DOI: 10.1038/s41467-024-50141-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024] Open
Abstract
Exploring the promiscuity of native enzymes presents a promising strategy for expanding their synthetic applications, particularly for catalyzing challenging reactions in non-native contexts. In this study, we explore the promiscuous potential of old yellow enzymes (OYEs) to facilitate the Morita-Baylis-Hillman reaction (MBH reaction), leveraging substrate similarities between MBH reaction and reduction reaction. Using mass spectrometry and spectroscopic techniques, we confirm promiscuity of GkOYE in both MBH and reduction reactions. By blocking H- and H+ transfer pathways, we engineer GkOYE.8, which loses its reduction ability but enhances its MBH activity. The structural basis of MBH reaction catalyzed by GkOYE.8 is obtained through mutation studies and kinetic simulations. Furthermore, enantiocomplementary mutants GkOYE.11 and GkOYE.13 are obtained by directed evolution, exhibiting the ability to accept various aromatic aldehydes and alkenes as substrates. This study demonstrates the potential of leveraging substrate similarities to unlock enzyme functionalities, enabling the catalysis of new-to-nature reactions.
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Affiliation(s)
- Lei Wang
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Yaoyun Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jun Hu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Dejing Yin
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
| | - Wanqing Wei
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jian Wen
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Xiulai Chen
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Cong Gao
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Yiwen Zhou
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Jia Liu
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Guipeng Hu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Xiaomin Li
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Jing Wu
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Zhi Zhou
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China
| | - Liming Liu
- School of Biotechnology, Jiangnan University, Wuxi, 214122, China
- Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi, 214122, China
| | - Wei Song
- School of Life Sciences and Health Engineering, Jiangnan University, Wuxi, 214122, China.
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2
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Kerschbaumer B, Totaro MG, Friess M, Breinbauer R, Bijelic A, Macheroux P. Loop 6 and the β-hairpin flap are structural hotspots that determine cofactor specificity in the FMN-dependent family of ene-reductases. FEBS J 2024; 291:1560-1574. [PMID: 38263933 DOI: 10.1111/febs.17055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/04/2023] [Accepted: 01/08/2024] [Indexed: 01/25/2024]
Abstract
Flavin mononucleotide (FMN)-dependent ene-reductases constitute a large family of oxidoreductases that catalyze the enantiospecific reduction of carbon-carbon double bonds. The reducing equivalents required for substrate reduction are obtained from reduced nicotinamide by hydride transfer. Most ene-reductases significantly prefer, or exclusively accept, either NADPH or NADH. Despite their usefulness in biocatalytic applications, the structural determinants for cofactor preference remain elusive. We employed the NADPH-preferring 12-oxophytodienoic acid reductase 3 from Solanum lycopersicum (SlOPR3) as a model enzyme of the ene-reductase family and applied computational and structural methods to investigate the binding specificity of the reducing coenzymes. Initial docking results indicated that the arginine triad R283, R343, and R366 residing on and close to a critical loop at the active site (loop 6) are the main contributors to NADPH binding. In contrast, NADH binds unfavorably in the opposite direction toward the β-hairpin flap within a largely hydrophobic region. Notably, the crystal structures of SlOPR3 in complex with either NADPH4 or NADH4 corroborated these different binding modes. Molecular dynamics simulations confirmed NADH binding near the β-hairpin flap and provided structural explanations for the low binding affinity of NADH to SlOPR3. We postulate that cofactor specificity is determined by the arginine triad/loop 6 and the residue(s) controlling access to a hydrophobic cleft formed by the β-hairpin flap. Thus, NADPH preference depends on a properly positioned arginine triad, whereas granting access to the hydrophobic cleft at the β-hairpin flap favors NADH binding.
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Affiliation(s)
| | - Massimo G Totaro
- Institute of Biochemistry, Graz University of Technology, Austria
| | - Michael Friess
- Institute of Organic Chemistry, Graz University of Technology, Austria
| | - Rolf Breinbauer
- Institute of Organic Chemistry, Graz University of Technology, Austria
| | | | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, Austria
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3
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Petchey MR, Ye Y, Spelling V, Finnigan JD, Gittings S, Johansson MJ, Hayes MA, Hyster TK. Regiodivergent Radical Termination for Intermolecular Biocatalytic C-C Bond Formation. J Am Chem Soc 2024; 146:5005-5010. [PMID: 38329236 PMCID: PMC10885151 DOI: 10.1021/jacs.4c00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
Radical hydrofunctionalizations of electronically unbiased dienes are challenging to render regioselective, because the products are nearly identical in energy. Here, we report two engineered FMN-dependent "ene"-reductases (EREDs) that catalyze regiodivergent hydroalkylations of cyclic and linear dienes. While previous studies focused exclusively on the stereoselectivity of alkene hydroalkylation, this work highlights that EREDs can control the regioselectivity of hydrogen atom transfer, providing a method for selectively preparing constitutional isomers that would be challenging to prepare using traditional synthetic methods. Engineering the ERED from Gluconabacter sp. (GluER) furnished a variant that favors the γ,δ-unsaturated ketone, while an engineered variant from a commercial ERED panel favors the δ,ε-unsaturated ketone. The effect of beneficial mutations has been investigated using substrate docking studies and the mechanism probed by isotope labeling experiments. A variety of α-bromo ketones can be coupled with cyclic and linear dienes. These interesting building blocks can also be further modified to generate difficult-to-access heterocyclic compounds.
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Affiliation(s)
- Mark R. Petchey
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Yuxuan Ye
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
| | - Victor Spelling
- Early
Chemical Development, Pharmaceutical Sciences, BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - James D. Finnigan
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Samantha Gittings
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Magnus J. Johansson
- Medicinal
Chemistry, Research and Early Development, Cardiovascular, Renal and
Metabolism (CVRM), BioPharma R&D, AstraZeneca, Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Martin A. Hayes
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Todd K. Hyster
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
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4
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Singh Y, Sharma R, Mishra M, Verma PK, Saxena AK. Crystal structure of ArOYE6 reveals a novel C‐terminal helical extension and mechanistic insights into the distinct class III OYEs from pathogenic fungi. FEBS J 2022; 289:5531-5550. [DOI: 10.1111/febs.16445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/02/2022] [Accepted: 03/18/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Yeshveer Singh
- Plant Immunity Laboratory National Institute of Plant Genome Research New Delhi India
| | - Ruby Sharma
- Rm‐403/440 Structural Biology Laboratory School of Life Science Jawaharlal Nehru University New Delhi India
| | - Manasi Mishra
- Plant Immunity Laboratory National Institute of Plant Genome Research New Delhi India
| | - Praveen Kumar Verma
- Plant Immunity Laboratory National Institute of Plant Genome Research New Delhi India
- Plant Immunity Laboratory School of Life Science Jawaharlal Nehru University New Delhi India
| | - Ajay Kumar Saxena
- Rm‐403/440 Structural Biology Laboratory School of Life Science Jawaharlal Nehru University New Delhi India
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5
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Robescu MS, Loprete G, Gasparotto M, Vascon F, Filippini F, Cendron L, Bergantino E. The Family Keeps on Growing: Four Novel Fungal OYEs Characterized. Int J Mol Sci 2022; 23:ijms23063050. [PMID: 35328465 PMCID: PMC8954901 DOI: 10.3390/ijms23063050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/07/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022] Open
Abstract
Aiming at expanding the portfolio of Old Yellow Enzymes (OYEs), which have been systematically studied to be employed in the chemical and pharmaceutical industries as useful biocatalysts, we decided to explore the immense reservoir of filamentous fungi. We drew from the genome of the two Ascomycetes Aspergillus niger and Botryotinia fuckeliana four new members of the OYE superfamily belonging to the classical and thermophilic-like subfamilies. The two BfOYEs show wider substrate spectra than the AnOYE homologues, which appear as more specialized biocatalysts. According to their mesophilic origins, the new enzymes neither show high thermostability nor extreme pH optimums. The crystal structures of BfOYE4 and AnOYE8 have been determined, revealing the conserved features of the thermophilic-like subclass as well as unique properties, such as a peculiar N-terminal loop involved in dimer surface interactions. For the classical representatives BfOYE1 and AnOYE2, model structures were built and analyzed, showing surprisingly wide open access to the active site cavities due to a shorter β6-loop and a disordered capping subdomain.
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6
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Shi Q, Jia Y, Wang H, Li S, Li H, Guo J, Dou T, Qin B, You S. Identification of four ene reductases and their preliminary exploration in the asymmetric synthesis of (R)-dihydrocarvone and (R)-profen derivatives. Enzyme Microb Technol 2021; 150:109880. [PMID: 34489033 DOI: 10.1016/j.enzmictec.2021.109880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 11/16/2022]
Abstract
The ene reductases (ERs) from the old yellow enzymes (OYEs) family have the ability to reduce activated alkenes to generate up to two stereocenters, therefore they have been received extensive attention as powerful biocatalysts. In this study, through gene mining, four ERs were identified from the genomes of Ensifer adhaerens, Pseudomonas fluorescens, and Pseudomonas veronil. The biocatalytic properties of these four ERs were identified, and their applications in the synthesis process of dihydrocarvone and profen derivatives were further evaluated. Among them, three ERs (EaER2, PvER1, and PvER2) belonging to the classic OYEs showed the best catalytic activity at 30 °C and pH 7.0 (100 mM potassium phosphate buffer) and the PfER2, which belongs to the thermophilic-like OYEs exhibited the best catalytic at 40 °C and pH 7.0 (100 mM potassium phosphate buffer). When exploring the influence of organic solvents on the catalytic efficiency, it was found that the four ERs were more sensitive to toluene and had tolerance to several other selected organic solvents. In addition, EaER2, PfER2, PvER1 and PvER2 showed excellent catalytic activity toward carvone, and the stereoselectivity of PvER2 toward carvone could reach up to 88.7 % de. EaER2 and PfER2 can catalyze the synthesis of a variety of profen derivatives with a stereoselectivity over 99 % ee. Moreover, through homology modeling and molecular docking, we preliminarily explained the mechanism of catalytic activity and stereoselectivity of the four ERs, which provided a solid base on the rational design of their stereo-preference in the future. The discovery of EaER2, PfER2, PvER1, and PvER2 provides four new enzyme sources for the study of the OYEs family and enriches the biocatalytic toolbox of ERs. Our exploration of the enzymatic properties of these four ERs will provide the sufficient data basis for future research and industrialization progress.
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Affiliation(s)
- Qinghua Shi
- School of Life Sciences and Biopharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Yutian Jia
- School of Life Sciences and Biopharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Huibin Wang
- School of Pharmacy, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Shang Li
- Wuya College of Innovation, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Hengyu Li
- School of Life Sciences and Biopharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Jiyang Guo
- School of Life Sciences and Biopharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Tong Dou
- Wuya College of Innovation, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China
| | - Bin Qin
- Wuya College of Innovation, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China.
| | - Song You
- School of Life Sciences and Biopharmaceutical Sciences, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe, Shenyang, 110016, People's Republic of China.
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7
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Forouzesh DC, Beaupre BA, Butrin A, Wawrzak Z, Liu D, Moran GR. The Interaction of Porcine Dihydropyrimidine Dehydrogenase with the Chemotherapy Sensitizer: 5-Ethynyluracil. Biochemistry 2021; 60:1120-1132. [PMID: 33755421 DOI: 10.1021/acs.biochem.1c00096] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dihydropyrimidine dehydrogenase (DPD) is a complex enzyme that reduces the 5,6-vinylic bond of pyrimidines, uracil, and thymine. 5-Fluorouracil (5FU) is also a substrate for DPD and a common chemotherapeutic agent used to treat numerous cancers. The reduction of 5FU to 5-fluoro-5,6-dihydrouracil negates its toxicity and efficacy. Patients with high DPD activity levels typically have poor outcomes when treated with 5FU. DPD is thus a central mitigating factor in the treatment of a variety of cancers. 5-Ethynyluracil (5EU) covalently inactivates DPD by cross-linking with the active-site general acid cysteine in the pyrimidine binding site. This reaction is dependent on the simultaneous binding of 5EU and nicotinamide adenine dinucleotide phosphate (NADPH). This ternary complex induces DPD to become activated by taking up two electrons from the NADPH. The covalent inactivation of DPD by 5EU occurs concomitantly with this reductive activation with a rate constant of ∼0.2 s-1. This kinact value is correlated with the rate of reduction of one of the two flavin cofactors and the localization of a mobile loop in the pyrimidine active site that places the cysteine that serves as the general acid in catalysis proximal to the 5EU ethynyl group. Efficient cross-linking is reliant on enzyme activation, but this process appears to also have a conformational aspect in that nonreductive NADPH analogues can also induce a partial inactivation. Cross-linking then renders DPD inactive by severing the proton-coupled electron transfer mechanism that transmits electrons 56 Å across the protein.
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Affiliation(s)
- Dariush C Forouzesh
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States
| | - Brett A Beaupre
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States
| | - Arseniy Butrin
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States
| | - Zdzislaw Wawrzak
- Synchrotron Research Center, Life Sciences Collaborative Access Team, Northwestern University, Argonne, Illinois 60439, United States
| | - Dali Liu
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States
| | - Graham R Moran
- Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W Sheridan RoadChicago, Illinois 60660, United States
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8
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Page CG, Cooper SJ, DeHovitz JS, Oblinsky DG, Biegasiewicz KF, Antropow AH, Armbrust KW, Ellis JM, Hamann LG, Horn EJ, Oberg KM, Scholes GD, Hyster TK. Quaternary Charge-Transfer Complex Enables Photoenzymatic Intermolecular Hydroalkylation of Olefins. J Am Chem Soc 2021; 143:97-102. [PMID: 33369395 PMCID: PMC7832516 DOI: 10.1021/jacs.0c11462] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Intermolecular C-C bond-forming reactions are underdeveloped transformations in the field of biocatalysis. Here we report a photoenzymatic intermolecular hydroalkylation of olefins catalyzed by flavin-dependent 'ene'-reductases. Radical initiation occurs via photoexcitation of a rare high-order enzyme-templated charge-transfer complex that forms between an alkene, α-chloroamide, and flavin hydroquinone. This unique mechanism ensures that radical formation only occurs when both substrates are present within the protein active site. This active site can control the radical terminating hydrogen atom transfer, enabling the synthesis of enantioenriched γ-stereogenic amides. This work highlights the potential for photoenzymatic catalysis to enable new biocatalytic transformations via previously unknown electron transfer mechanisms.
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Affiliation(s)
- Claire G. Page
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
| | - Simon J. Cooper
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
| | - Jacob S. DeHovitz
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
| | - Daniel G. Oblinsky
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
| | | | - Alyssa H. Antropow
- Bristol Myers Squibb, 200 Cambridge Park Drive,
Suite 3000, Cambridge, Massachusetts, 02140 USA
| | - Kurt W. Armbrust
- Bristol Myers Squibb, 200 Cambridge Park Drive,
Suite 3000, Cambridge, Massachusetts, 02140 USA
| | - J. Michael Ellis
- Bristol Myers Squibb, 200 Cambridge Park Drive,
Suite 3000, Cambridge, Massachusetts, 02140 USA
| | - Lawrence G. Hamann
- Takeda Pharmaceuticals, 30 Landsdowne Street,
Cambridge, Massachusetts, 02139, USA
| | - Evan J. Horn
- Bristol Myers Squibb, 10300 Campus Point Drive,
Suite 100, San Diego, California, 92121 USA
| | - Kevin M. Oberg
- Bristol Myers Squibb, 10300 Campus Point Drive,
Suite 100, San Diego, California, 92121 USA
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
| | - Todd K. Hyster
- Department of Chemistry, Princeton University, Princeton,
New Jersey, 08544 USA
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9
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Old yellow enzymes: structures and structure-guided engineering for stereocomplementary bioreduction. Appl Microbiol Biotechnol 2020; 104:8155-8170. [PMID: 32830294 DOI: 10.1007/s00253-020-10845-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 10/23/2022]
Abstract
Since the first discovery of old yellow enzyme 1 (OYE1) from Saccharomyces pastorianus in 1932, biocatalytic asymmetric reduction of activated alkenes by OYEs has become a valuable reaction in organic synthesis. To access stereocomplementary C=C-bond bioreduction, the mining of novel OYEs and especially the protein engineering of existing OYEs have been performed, which successfully achieved the stereocomplementary reduction in several cases and further raise the potential of applications. In this review, we analyzed the structures, active sites, and substrate recognition of OYEs, which are the bases for their substrate specificity and stereospecificity. Sequence similarity network of OYEs superfamily was also constructed to investigate the scope of characterized OYEs. The structure-guided engineering to switch the stereoselectivity of OYEs and thus access stereocomplementary bioreduction over the last decade (2009-2020) was then reviewed and discussed, which might give new insights into the mining and engineering of related biocatalysts. KEY POINTS: • The sequence similarity network of OYEs superfamily was constructed and annotated. • The structures and active sites of OYEs from different classes were compared. • "Left/right" binding mode was used to explain the stereopreferences of OYEs. • Structure-guided engineering of OYEs to switch their stereoselectivity was reviewed.
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10
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Roman JV, Melkonian TR, Silvaggi NR, Moran GR. Transient-State Analysis of Human Isocitrate Dehydrogenase I: Accounting for the Interconversion of Active and Non-Active Conformational States. Biochemistry 2019; 58:5366-5380. [PMID: 31478653 DOI: 10.1021/acs.biochem.9b00518] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Human isocitrate dehydrogenase 1 (HsICDH1) is a cytoplasmic homodimeric Mg(II)-dependent enzyme that converts d-isocitrate (D-ICT) and NADP+ to α-ketoglutarate (AKG), CO2, and NADPH. The active sites are formed at the subunit interface and incorporate residues from both protomers. The turnover number titrates hyperbolically from 17.5 s-1 to a minimum of 7 s-1 with an increasing enzyme concentration. As isolated, the enzyme adopts an inactive open conformation and binds NADPH tightly. The open conformation displaces three of the eight residues that bind D-ICT and Mg(II). Enzyme activation occurs with the addition of Mg(II) or D-ICT with a rate constant of 0.12 s-1. The addition of both Mg(II) and D-ICT activates the enzyme with a rate constant of 0.6 s-1 and displaces half of the bound NADPH. This indicates that HsICDH1 may have a half-site mechanism in which the active sites alternate in catalysis. The X-ray crystal structure of the half-site activated complex reveals asymmetry in the homodimer with a single NADPH bound. The structure also indicates a pseudotetramer interface that impedes the egress of NADPH consistent with the suppression of the turnover number at high enzyme concentrations. When the half-site activated form of the enzyme is reacted with NADP+, NADPH forms with a rate constant of 204 s-1 followed by a shift in the NADPH absorption spectrum with a rate constant of 28 s-1. These data indicate the accumulation of two intermediate states. Once D-ICT is exhausted, HsICDH1 relaxes to the inactive open state with a rate constant of ∼3 s-1.
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Affiliation(s)
- Joseph V Roman
- Department of Chemistry and Biochemistry , Loyola University Chicago , Flanner Hall, 1068 West Sheridan Road , Chicago , Illinois 60660 , United States
| | - Trevor R Melkonian
- Department of Chemistry and Biochemistry , University of Wisconsin-Milwaukee , 3210 North Cramer Street , Milwaukee , Wisconsin 53211-3209 , United States
| | - Nicholas R Silvaggi
- Department of Chemistry and Biochemistry , University of Wisconsin-Milwaukee , 3210 North Cramer Street , Milwaukee , Wisconsin 53211-3209 , United States
| | - Graham R Moran
- Department of Chemistry and Biochemistry , Loyola University Chicago , Flanner Hall, 1068 West Sheridan Road , Chicago , Illinois 60660 , United States
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11
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Peters C, Frasson D, Sievers M, Buller R. Novel Old Yellow Enzyme Subclasses. Chembiochem 2019; 20:1569-1577. [DOI: 10.1002/cbic.201800770] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 02/12/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Christin Peters
- Competence Center for BiocatalysisInstitute of Chemistry and BiotechnologySchool of Life Sciences and Facility ManagementZurich University of Applied Sciences Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - David Frasson
- Molecular BiologyInstitute of Chemistry and BiotechnologySchool of Life Sciences and Facility ManagementZurich University of Applied Sciences Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Martin Sievers
- Molecular BiologyInstitute of Chemistry and BiotechnologySchool of Life Sciences and Facility ManagementZurich University of Applied Sciences Einsiedlerstrasse 31 8820 Wädenswil Switzerland
| | - Rebecca Buller
- Competence Center for BiocatalysisInstitute of Chemistry and BiotechnologySchool of Life Sciences and Facility ManagementZurich University of Applied Sciences Einsiedlerstrasse 31 8820 Wädenswil Switzerland
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12
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Veloso-Silva LLW, Dores-Silva PR, Bertolino-Reis DE, Moreno-Oliveira LF, Libardi SH, Borges JC. Structural studies of Old Yellow Enzyme of Leishmania braziliensis in solution. Arch Biochem Biophys 2019; 661:87-96. [DOI: 10.1016/j.abb.2018.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Revised: 11/10/2018] [Accepted: 11/11/2018] [Indexed: 01/18/2023]
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13
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Kawada Y, Goshima T, Sawamura R, Yokoyama SI, Yanase E, Niwa T, Ebihara A, Inagaki M, Yamaguchi K, Kuwata K, Kato Y, Sakurada O, Suzuki T. Daidzein reductase of Eggerthella sp. YY7918, its octameric subunit structure containing FMN/FAD/4Fe-4S, and its enantioselective production of R-dihydroisoflavones. J Biosci Bioeng 2018; 126:301-309. [PMID: 29699942 DOI: 10.1016/j.jbiosc.2018.03.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 03/20/2018] [Accepted: 03/23/2018] [Indexed: 12/29/2022]
Abstract
S-Equol is a metabolite of daidzein, a type of soy isoflavone, and three reductases are involved in the conversion of daidzein by specific intestinal bacteria. S-Equol is thought to prevent hormone-dependent diseases. We previously identified the equol producing gene cluster (eqlABC) of Eggerthella sp. YY7918. Daidzein reductase (DZNR), encoded by eqlA, catalyzes the reduction of daidzein to dihydrodaidzein (the first step of equol synthesis), which was confirmed using a recombinant enzyme produced in Escherichia coli. Here, we purified recombinant DZNR to homogeneity and analyzed its enzymological properties. DZNR contained FMN, FAD, and one 4Fe-4S cluster per 70-kDa subunit as enzymatic cofactors. DZNR reduced the CC bond between the C-2 and C-3 positions of daidzein, genistein, glycitein, and formononetin in the presence of NADPH. R-Dihydrodaidzein and R-dihydrogenistein were highly stereo-selectively produced from daidzein and genistein. The Km and kcat for daidzein were 11.9 μM and 6.7 s-1, and these values for genistein were 74.1 μM and 28.3 s-1, respectively. This enzyme showed similar kinetic parameters and wide substrate specificity for isoflavone molecules. Thus, this enzyme appears to be an isoflavone reductase. Gel filtration chromatography and chemical cross-linking analysis of the active form of DZNR suggested that the enzyme consists of an octameric subunit structure. We confirmed this by small-angle X-ray scattering and transmission electron microscopy at a magnification of ×200,000. DZNR formed a globular four-petal cloverleaf structure with a central vertical hole. The maximum particle size was 173 Å.
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Affiliation(s)
- Yuika Kawada
- United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Tomoko Goshima
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Rie Sawamura
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Shin-Ichiro Yokoyama
- Department of Food Technology, Industrial Technology Center, Gifu Prefectural Government, 47 Kitaoyobi, Kasamatsu, Hashima, Gifu 501-6064, Japan
| | - Emiko Yanase
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Toshio Niwa
- Faculty of Health and Nutrition, Shubun University, 6 Nikko-cho, Ichinomiya, Aichi 491-0938, Japan
| | - Akio Ebihara
- United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Center for Highly Advanced Integration of Nano and Life Sciences, Gifu University (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Mizuho Inagaki
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Keiichi Yamaguchi
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Kazuo Kuwata
- United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Center for Highly Advanced Integration of Nano and Life Sciences, Gifu University (G-CHAIN), Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Yuta Kato
- Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Osamu Sakurada
- Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
| | - Tohru Suzuki
- United Graduate School of Agricultural Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan; Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
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14
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Gonçalves AC, Carneiro ZA, Oliveira CG, Danuello A, Guerra W, Oliveira RJ, Ferreira FB, Veloso-Silva LL, Batista FA, Borges JC, de Albuquerque S, Deflon VM, Maia PI. Pt II , Pd II and Au III complexes with a thiosemicarbazone derived from diacethylmonooxime: Structural analysis, trypanocidal activity, cytotoxicity and first insight into the antiparasitic mechanism of action. Eur J Med Chem 2017; 141:615-631. [DOI: 10.1016/j.ejmech.2017.10.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 09/19/2017] [Accepted: 10/07/2017] [Indexed: 11/28/2022]
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15
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Romagnolo A, Spina F, Poli A, Risso S, Serito B, Crotti M, Monti D, Brenna E, Lanfranco L, Varese GC. Old Yellow Enzyme homologues in Mucor circinelloides: expression profile and biotransformation. Sci Rep 2017; 7:12093. [PMID: 28935878 PMCID: PMC5608841 DOI: 10.1038/s41598-017-12545-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/06/2017] [Indexed: 12/05/2022] Open
Abstract
The reduction of C=C double bond, a key reaction in organic synthesis, is mostly achieved by traditional chemical methods. Therefore, the search for enzymes capable of performing this reaction is rapidly increasing. Old Yellow Enzymes (OYEs) are flavin-dependent oxidoreductases, initially isolated from Saccharomyces pastorianus. In this study, the presence and activation of putative OYE enzymes was investigated in the filamentous fungus Mucor circinelloides, which was previously found to mediate C=C reduction. Following an in silico approach, using S. pastorianus OYE1 amminoacidic sequence as template, ten putative genes were identified in the genome of M. circinelloides. A phylogenetic analysis revealed a high homology of McOYE1-9 with OYE1-like proteins while McOYE10 showed similarity with thermophilic-like OYEs. The activation of mcoyes was evaluated during the transformation of three different model substrates. Cyclohexenone, α-methylcinnamaldehyde and methyl cinnamate were completely reduced in few hours and the induction of gene expression, assessed by qRT-PCR, was generally fast, suggesting a substrate-dependent activation. Eight genes were activated in the tested conditions suggesting that they may encode for active OYEs. Their expression over time correlated with C=C double bond reduction.
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Affiliation(s)
- Alice Romagnolo
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Federica Spina
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Anna Poli
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Sara Risso
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Bianca Serito
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Michele Crotti
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, via L. Mancinelli 7, 20131, Milan, Italy
| | - Daniela Monti
- Istituto di Chimica del Riconoscimento Molecolare, CNR, Via M. Bianco 9, 20131, Milan, Italy
| | - Elisabetta Brenna
- Department of Chemistry, Materials and Chemical Engineering "G. Natta", Politecnico di Milano, via L. Mancinelli 7, 20131, Milan, Italy
| | - Luisa Lanfranco
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy
| | - Giovanna Cristina Varese
- Department of Life Sciences and Systems Biology, University of Turin, viale P. A. Mattioli 25, 10125, Turin, Italy.
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Verma S, Gazara RK, Verma PK. Transcription Factor Repertoire of Necrotrophic Fungal Phytopathogen Ascochyta rabiei: Predominance of MYB Transcription Factors As Potential Regulators of Secretome. FRONTIERS IN PLANT SCIENCE 2017; 8:1037. [PMID: 28659964 PMCID: PMC5470089 DOI: 10.3389/fpls.2017.01037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/30/2017] [Indexed: 06/02/2023]
Abstract
Transcription factors (TFs) are the key players in gene expression and their study is highly significant for shedding light on the molecular mechanisms and evolutionary history of organisms. During host-pathogen interaction, extensive reprogramming of gene expression facilitated by TFs is likely to occur in both host and pathogen. To date, the knowledge about TF repertoire in filamentous fungi is in infancy. The necrotrophic fungus Ascochyta rabiei, that causes destructive Ascochyta blight (AB) disease of chickpea (Cicer arietinum), demands more comprehensive study for better understanding of Ascochyta-legume pathosystem. In the present study, we performed the genome-wide identification and analysis of TFs in A. rabiei. Taking advantage of A. rabiei genome sequence, we used a bioinformatic approach to predict the TF repertoire of A. rabiei. For identification and classification of A. rabiei TFs, we designed a comprehensive pipeline using a combination of BLAST and InterProScan software. A total of 381 A. rabiei TFs were predicted and divided into 32 fungal specific families of TFs. The gene structure, domain organization and phylogenetic analysis of abundant families of A. rabiei TFs were also carried out. Comparative study of A. rabiei TFs with that of other necrotrophic, biotrophic, hemibiotrophic, symbiotic, and saprotrophic fungi was performed. It suggested presence of both conserved as well as unique features among them. Moreover, cis-acting elements on promoter sequences of earlier predicted A. rabiei secretome were also identified. With the help of published A. rabiei transcriptome data, the differential expression of TF and secretory protein coding genes was analyzed. Furthermore, comprehensive expression analysis of few selected A. rabiei TFs using quantitative real-time polymerase chain reaction revealed variety of expression patterns during host colonization. These genes were expressed in at least one of the time points tested post infection. Overall, this study illustrates the first genome-wide identification and analysis of TF repertoire of A. rabiei. This work would provide the basis for further studies to dissect role of TFs in the molecular mechanisms during A. rabiei-chickpea interactions.
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Affiliation(s)
| | | | - Praveen K. Verma
- Plant Immunity Laboratory, National Institute of Plant Genome ResearchNew Delhi, India
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17
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Waller J, Toogood HS, Karuppiah V, Rattray NJW, Mansell DJ, Leys D, Gardiner JM, Fryszkowska A, Ahmed ST, Bandichhor R, Reddy GP, Scrutton NS. Structural insights into the ene-reductase synthesis of profens. Org Biomol Chem 2017; 15:4440-4448. [PMID: 28485453 DOI: 10.1039/c7ob00163k] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reduction of double bonds of α,β-unsaturated carboxylic acids and esters by ene-reductases remains challenging and it typically requires activation by a second electron-withdrawing moiety, such as a halide or second carboxylate group. We showed that profen precursors, 2-arylpropenoic acids and their esters, were efficiently reduced by Old Yellow Enzymes (OYEs). The XenA and GYE enzymes showed activity towards acids, while a wider range of enzymes were active towards the equivalent methyl esters. Comparative co-crystal structural analysis of profen-bound OYEs highlighted key interactions important in determining substrate binding in a catalytically active conformation. The general utility of ene reductases for the synthesis of (R)-profens was established and this work will now drive future mutagenesis studies to screen for the production of pharmaceutically-active (S)-profens.
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Affiliation(s)
- J Waller
- Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
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18
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Old Yellow Enzyme-Catalysed Asymmetric Hydrogenation: Linking Family Roots with Improved Catalysis. Catalysts 2017. [DOI: 10.3390/catal7050130] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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19
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Catucci G, Romagnolo A, Spina F, Varese GC, Gilardi G, Di Nardo G. Enzyme-substrate matching in biocatalysis: in silico studies to predict substrate preference of ten putative ene-reductases from Mucor circinelloides MUT44. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2016.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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20
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Verma S, Gazara RK, Nizam S, Parween S, Chattopadhyay D, Verma PK. Draft genome sequencing and secretome analysis of fungal phytopathogen Ascochyta rabiei provides insight into the necrotrophic effector repertoire. Sci Rep 2016; 6:24638. [PMID: 27091329 PMCID: PMC4835772 DOI: 10.1038/srep24638] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 04/04/2016] [Indexed: 01/28/2023] Open
Abstract
Constant evolutionary pressure acting on pathogens refines their molecular strategies to attain successful pathogenesis. Recent studies have shown that pathogenicity mechanisms of necrotrophic fungi are far more intricate than earlier evaluated. However, only a few studies have explored necrotrophic fungal pathogens. Ascochyta rabiei is a necrotrophic fungus that causes devastating blight disease of chickpea (Cicer arietinum). Here, we report a 34.6 megabase draft genome assembly of A. rabiei. The genome assembly covered more than 99% of the gene space and 4,259 simple sequence repeats were identified in the assembly. A total of 10,596 high confidence protein-coding genes were predicted which includes a large and diverse inventory of secretory proteins, transporters and primary and secondary metabolism enzymes reflecting the necrotrophic lifestyle of A. rabiei. A wide range of genes encoding carbohydrate-active enzymes capable for degradation of complex polysaccharides were also identified. Comprehensive analysis predicted a set of 758 secretory proteins including both classical and non-classical secreted proteins. Several of these predicted secretory proteins showed high cysteine content and numerous tandem repeats. Together, our analyses would broadly expand our knowledge and offer insights into the pathogenesis and necrotrophic lifestyle of fungal phytopathogens.
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Affiliation(s)
- Sandhya Verma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Rajesh Kumar Gazara
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Shadab Nizam
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Sabiha Parween
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Debasis Chattopadhyay
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
| | - Praveen Kumar Verma
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
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Srivastava V, Verma PK. Genome Wide Identification of LIM Genes in Cicer arietinum and Response of Ca-2LIMs in Development, Hormone and Pathogenic Stress. PLoS One 2015; 10:e0138719. [PMID: 26418014 PMCID: PMC4587737 DOI: 10.1371/journal.pone.0138719] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 09/02/2015] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic lineage-specific LIM protein (LIN11, ISL1, and MEC3) family play pivotal role in modulation of actin dynamics and transcriptional regulation. The systematic investigation of this family has not been carried in detail and rare in legumes. Current study involves the mining of Cicer arietinum genome for the genes coding for LIM domain proteins and displayed significant homology with LIM genes of other species. The analysis led to the identification of 15 members, which were positioned on chickpea chromosomes. The phylogenetic and motif analysis suggested their categorization into two sub-families i.e., Ca-2LIMs and Ca-DA1/DAR, which comprised of nine and six candidates, respectively. Further sub-categories of Ca-2LIMs were recognised as αLIM, βLIM, δLIM and γLIM. The LIM genes within their sub-families displayed conserved genomic and motif organization. The expression pattern of Ca-2LIMs across developmental and reproductive tissues demonstrated strong correlation with established consensus. The Ca-2LIM belongs to PLIM and GLIM (XLIM) was found highly expressed in floral tissue. Others showed ubiquitous expression pattern with their dominance in stem. Under hormonal and pathogenic conditions these LIMs were found to up-regulate during salicylic acid, abscisic acid and Ascochyta rabiei treatment or infection; and down-regulated in response to jasmonic acid treatment. The findings of this work, particularly in terms of modulation of LIM genes under biotic stress will open up the way to further explore and establish the role of chickpea LIMs in plant defense response.
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Affiliation(s)
- Vikas Srivastava
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
| | - Praveen Kumar Verma
- Plant Immunity Laboratory, National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi, India
- * E-mail:
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Characterization and proteomic analysis of the Pseudomonas sp. HK-6 xenB knockout mutant under RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) stress. Curr Microbiol 2014; 70:119-27. [PMID: 25239011 DOI: 10.1007/s00284-014-0688-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/30/2014] [Indexed: 10/24/2022]
Abstract
Pseudomonas sp. HK-6 is able to utilize RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) as its sole nitrogen source. The role of the xenB gene, encoding xenobiotic reductase B, was investigated using HK-6 xenB knockout mutants. The xenB mutant degraded RDX to a level that was 10-fold less than that obtained with the wild-type HK-6 strain. After 60 days of culture with 25 or 50 μM RDX, no residual RDX was detected in the supernatants of the wild-type aerobically grown cultures, whereas approximately 90 % of the RDX remained in the xenB mutant cultures. The xenB mutant bacteria exhibited a 10(2)-10(4)-fold decrease in survival rate compared to the wild-type. The expression of DnaK and GroEL proteins, two typical stress shock proteins (SSPs), in the xenB mutant increased after immediate exposure to RDX, yet dramatically decreased after 4 h of exposure. In addition, DnaK and GroEL were more highly expressed in the cultures with 25 μM RDX in the medium but showed low expression in the cultures with 50 or 75 μM RDX. The expression levels of the dnaK and groEL genes measured by RT-qPCR were also much lower in the xenB genetic background. Analyses of the proteomes of the HK-6 and xenB mutant cells grown under conditions of RDX stress showed increased induction of several proteins, such as Alg8, alginate biosynthesis sensor histidine kinase, and OprH in the xenB mutants when compared to wild-type. However, many proteins, including two SSPs (DnaK and GroEL) and proteins involved in metabolism, exhibited lower expression levels in the xenB mutant than in the wild-type HK-6 strain. The xenB knockout mutation leads to reduced RDX degradation ability, which renders the mutant more sensitive to RDX stress and results in a lower survival rate and an altered proteomic profile under RDX stress.
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