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Manenda MS, Picard MÈ, Zhang L, Cyr N, Zhu X, Barma J, Pascal JM, Couture M, Zhang C, Shi R. Structural analyses of the Group A flavin-dependent monooxygenase PieE reveal a sliding FAD cofactor conformation bridging OUT and IN conformations. J Biol Chem 2020; 295:4709-4722. [PMID: 32111738 DOI: 10.1074/jbc.ra119.011212] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/26/2020] [Indexed: 02/02/2023] Open
Abstract
Group A flavin-dependent monooxygenases catalyze the cleavage of the oxygen-oxygen bond of dioxygen, followed by the incorporation of one oxygen atom into the substrate molecule with the aid of NADPH and FAD. These flavoenzymes play an important role in many biological processes, and their most distinct structural feature is the choreographed motions of flavin, which typically adopts two distinct conformations (OUT and IN) to fulfill its function. Notably, these enzymes seem to have evolved a delicate control system to avoid the futile cycle of NADPH oxidation and FAD reduction in the absence of substrate, but the molecular basis of this system remains elusive. Using protein crystallography, size-exclusion chromatography coupled to multi-angle light scattering (SEC-MALS), and small-angle X-ray scattering (SEC-SAXS) and activity assay, we report here a structural and biochemical characterization of PieE, a member of the Group A flavin-dependent monooxygenases involved in the biosynthesis of the antibiotic piericidin A1. This analysis revealed that PieE forms a unique hexamer. Moreover, we found, to the best of our knowledge for the first time, that in addition to the classical OUT and IN conformations, FAD possesses a "sliding" conformation that exists in between the OUT and IN conformations. This observation sheds light on the underlying mechanism of how the signal of substrate binding is transmitted to the FAD-binding site to efficiently initiate NADPH binding and FAD reduction. Our findings bridge a gap currently missing in the orchestrated order of chemical events catalyzed by this important class of enzymes.
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Affiliation(s)
- Mahder S Manenda
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - Marie-Ève Picard
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - Liping Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, RNAM Center for Marine Microbiology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Normand Cyr
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Xiaojun Zhu
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - Julie Barma
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - John M Pascal
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, Québec H3T 1J4, Canada
| | - Manon Couture
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada.,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
| | - Changsheng Zhang
- CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, RNAM Center for Marine Microbiology, Guangdong Key Laboratory of Marine Materia Medica, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Rong Shi
- Département de Biochimie, de Microbiologie, et de Bio-informatique, PROTEO, Université Laval, Québec G1V 0A6, Canada .,Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, Québec G1V 0A6, Canada
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Chenprakhon P, Wongnate T, Chaiyen P. Monooxygenation of aromatic compounds by flavin-dependent monooxygenases. Protein Sci 2020; 28:8-29. [PMID: 30311986 DOI: 10.1002/pro.3525] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 10/08/2018] [Accepted: 10/08/2018] [Indexed: 12/12/2022]
Abstract
Many flavoenzymes catalyze hydroxylation of aromatic compounds especially phenolic compounds have been isolated and characterized. These enzymes can be classified as either single-component or two-component flavin-dependent hydroxylases (monooxygenases). The hydroxylation reactions catalyzed by the enzymes in this group are useful for modifying the biological properties of phenolic compounds. This review aims to provide an in-depth discussion of the current mechanistic understanding of representative flavin-dependent monooxygenases including 3-hydroxy-benzoate 4-hydroxylase (PHBH, a single-component hydroxylase), 3-hydroxyphenylacetate 4-hydroxylase (HPAH, a two-component hydroxylase), and other monooxygenases which catalyze reactions in addition to hydroxylation, including 2-methyl-3-hydroxypyridine-5-carboxylate oxygenase (MHPCO, a single-component enzyme that catalyzes aromatic-ring cleavage), and HadA monooxygenase (a two-component enzyme that catalyzes additional group elimination reaction). These enzymes have different unique structural features which dictate their reactivity toward various substrates and influence their ability to stabilize flavin intermediates such as C4a-hydroperoxyflavin. Understanding the key catalytic residues and the active site environments important for governing enzyme reactivity will undoubtedly facilitate future work in enzyme engineering or enzyme redesign for the development of biocatalytic methods for the synthesis of valuable compounds.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, 73170, Thailand
| | - Thanyaporn Wongnate
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, 21210, Thailand.,Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, 14000, Thailand
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Lazar JT, Shuvalova L, Rosas-Lemus M, Kiryukhina O, Satchell KJF, Minasov G. Structural comparison of p-hydroxybenzoate hydroxylase (PobA) from Pseudomonas putida with PobA from other Pseudomonas spp. and other monooxygenases. Acta Crystallogr F Struct Biol Commun 2019; 75:507-514. [PMID: 31282871 PMCID: PMC6613441 DOI: 10.1107/s2053230x19008653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 06/17/2019] [Indexed: 11/10/2022] Open
Abstract
The crystal structure is reported of p-hydroxybenzoate hydroxylase (PobA) from Pseudomonas putida, a possible drug target to combat tetracycline resistance, in complex with flavin adenine dinucleotide (FAD). The structure was refined at 2.2 Å resolution with four polypeptide chains in the asymmetric unit. Based on the results of pairwise structure alignments, PobA from P. putida is structurally very similar to PobA from P. fluorescens and from P. aeruginosa. Key residues in the FAD-binding and substrate-binding sites of PobA are highly conserved spatially across the proteins from all three species. Additionally, the structure was compared with two enzymes from the broader class of oxygenases: 2-hydroxybiphenyl 3-monooxygenase (HbpA) from P. nitroreducens and 2-methyl-3-hydroxypyridine-5-carboxylic acid oxygenase (MHPCO) from Mesorhizobium japonicum. Despite having only 14% similarity in their primary sequences, pairwise structure alignments of PobA from P. putida with HbpA from P. nitroreducens and MHPCO from M. japonicum revealed local similarities between these structures. Key secondary-structure elements important for catalysis, such as the βαβ fold, β-sheet wall and α12 helix, are conserved across this expanded class of oxygenases.
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Affiliation(s)
- John T. Lazar
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60201, USA
| | - Ludmilla Shuvalova
- Department of Microbiology–Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Monica Rosas-Lemus
- Department of Microbiology–Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Olga Kiryukhina
- Department of Microbiology–Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Karla J. F. Satchell
- Department of Microbiology–Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - George Minasov
- Department of Microbiology–Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- Center for Structural Genomics of Infectious Diseases, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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Rodríguez Benítez A, Tweedy SE, Baker Dockrey SA, Lukowski AL, Wymore T, Khare D, Brooks CL, Palfey BA, Smith JL, Narayan ARH. Structural basis for selectivity in flavin-dependent monooxygenase-catalyzed oxidative dearomatization. ACS Catal 2019; 9:3633-3640. [PMID: 31346489 DOI: 10.1021/acscatal.8b04575] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Biocatalytic reactions embody many features of ideal chemical transformations, including the potential for impeccable selectivity, high catalytic efficiency, mild reaction conditions and the use of environmentally benign reagents. These advantages have created a demand for biocatalysts that expand the portfolio of complexity-generating reactions available to synthetic chemists. However, the tradeoff that often exists between the substrate scope of a biocatalyst and its selectivity limits the application of enzymes in synthesis. We recently demonstrated that a flavin-dependent monooxygenase, TropB, maintains high levels of site- and stereoselectivity across a range of structurally diverse substrates. Herein, we disclose the structural basis for substrate binding in TropB, which performs a synthetically challenging asymmetric oxidative dearomatization reaction with exquisite site- and stereoselectivity across a range of phenol substrates, providing a foundation for future protein engineering and reaction development efforts. Our hypothesis for substrate binding is informed by a crystal structure of TropB and molecular dynamics simulations with the corresponding computational TropB model and is supported by experimental data. In contrast to canonical class A FAD-dependent monooxygenases in which substrates bind in a protonated form, our data indicate that the phenolate form of the substrate binds in the active site. Furthermore, the substrate position is controlled through twopoint binding of the phenolate oxygen to Arg206 and Tyr239, which are shown to have distinct and essential roles in catalysis. Arg206 is involved in the reduction of the flavin cofactor, suggesting a role in flavin dynamics. Further, QM/MM simulations reveal the interactions that govern the facial selectivity that leads to a highly enantioselective transformation. Thus, the structural origins of the high levels of site-and stereoselectivity observed in reactions of TropB across a range of substrates are elucidated, providing a foundation for future protein engineering and reaction development efforts.
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