1
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Zhang Q, Chen Q, Shaik S, Wang B. Flavin-N5OOH Functions as both a Powerful Nucleophile and a Base in the Superfamily of Flavoenzymes. Angew Chem Int Ed Engl 2024; 63:e202318629. [PMID: 38299700 DOI: 10.1002/anie.202318629] [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: 12/08/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/02/2024]
Abstract
Flavoenzymes can mediate a large variety of oxidation reactions through the activation of oxygen. However, the O2 activation chemistry of flavin enzymes is not yet fully exploited. Normally, the O2 activation occurs at the C4a site of the flavin cofactor, yielding the flavin C4a-(hydro)hydroperoxyl species in monooxygenases or oxidases. Using extensive MD simulations, QM/MM calculations and QM calculations, our studies reveal the formation of the common nucleophilic species, Flavin-N5OOH, in two distinct flavoenzymes (RutA and EncM). Our studies show that Flavin-N5OOH acts as a powerful nucleophile that promotes C-N cleavage of uracil in RutA, and a powerful base in the deprotonation of substrates in EncM. We reason that Flavin-N5OOH can be a common reactive species in the superfamily of flavoenzymes, which accomplish generally selective general base catalysis and C-X (X=N, S, Cl, O) cleavage reactions that are otherwise challenging with solvated hydroxide ion base. These results expand our understanding of the chemistry and catalysis of flavoenzymes.
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Affiliation(s)
- Qiaoyu Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Qianqian Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904, Jerusalem, Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, P. R. China
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2
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Jiang Y, Kim A, Olive C, Lewis JC. Selective C-H Halogenation of Alkenes and Alkynes Using Flavin-Dependent Halogenases. Angew Chem Int Ed Engl 2024; 63:e202317860. [PMID: 38280216 PMCID: PMC10947852 DOI: 10.1002/anie.202317860] [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: 11/22/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 01/29/2024]
Abstract
Single component flavin-dependent halogenases (FDHs) possess both flavin reductase and FDH activity in a single enzyme. We recently reported that the single component FDH AetF catalyzes site-selective bromination and iodination of a variety of aromatic substrates and enantioselective bromolactonization and iodoetherification of styrenes bearing pendant carboxylic acid or alcohol substituents. Given this inherent reactivity and selectivity, we explored the utility of AetF as catalyst for alkene and alkyne C-H halogenation. We find that AetF catalyzes halogenation of a range of 1,1-disubstituted styrenes, often with high stereoselectivity. Despite the utility of haloalkenes for cross-coupling and other applications, accessing these compounds in a stereoselective manner typically requires functional group interconversion processes, and selective halogenation of 1,1'-disubstituted olefins remains rare. We also establish that AetF and homologues of this enzyme can halogenate terminal alkynes. Mutagenesis studies and deuterium kinetic isotope effects are used to support a mechanistic proposal involving covalent catalysis for halogenation of unactivated alkynes by AetF homologues. These findings expand the scope of FDH catalysis and continue to show the unique utility of single component FDHs for biocatalysis.
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Affiliation(s)
- Yuhua Jiang
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Ahram Kim
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Cahmlo Olive
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
| | - Jared C. Lewis
- Department of Chemistry, Indiana University, Bloomington, IN 47405, USA
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3
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Phintha A, Chaiyen P. Unifying and versatile features of flavin-dependent monooxygenases: Diverse catalysis by a common C4a-(hydro)peroxyflavin. J Biol Chem 2023; 299:105413. [PMID: 37918809 PMCID: PMC10696468 DOI: 10.1016/j.jbc.2023.105413] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/18/2023] [Accepted: 10/22/2023] [Indexed: 11/04/2023] Open
Abstract
Flavin-dependent monooxygenases (FDMOs) are known for their remarkable versatility and for their crucial roles in various biological processes and applications. Extensive research has been conducted to explore the structural and functional relationships of FDMOs. The majority of reported FDMOs utilize C4a-(hydro)peroxyflavin as a reactive intermediate to incorporate an oxygen atom into a wide range of compounds. This review discusses and analyzes recent advancements in our understanding of the structural and mechanistic features governing the enzyme functions. State-of-the-art discoveries related to common and distinct structural properties governing the catalytic versatility of the C4a-(hydro)peroxyflavin intermediate in selected FDMOs are discussed. Specifically, mechanisms of hydroxylation, dehalogenation, halogenation, and light-emitting reactions by FDMOs are highlighted. We also provide new analysis based on the structural and mechanistic features of these enzymes to gain insights into how the same intermediate can be harnessed to perform a wide variety of reactions. Challenging questions to obtain further breakthroughs in the understanding of FDMOs are also proposed.
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Affiliation(s)
- Aisaraphon Phintha
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand.
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4
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Ashaduzzaman M, Lingkon K, De Silva AJ, Bellizzi JJ. Crystallographic and thermodynamic evidence of negative cooperativity of flavin and tryptophan binding in the flavin-dependent halogenases AbeH and BorH. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554356. [PMID: 37662313 PMCID: PMC10473636 DOI: 10.1101/2023.08.22.554356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The flavin-dependent halogenase AbeH produces 5-chlorotryptophan in the biosynthetic pathway of the chlorinated bisindole alkaloid BE-54017. We report that in vitro, AbeH (assisted by the flavin reductase AbeF) can chlorinate and brominate tryptophan as well as other indole derivatives and substrates with phenyl and quinoline groups. We solved the X-ray crystal structures of AbeH alone and complexed with FAD, as well as crystal structures of the tryptophan-6-halogenase BorH alone, in complex with 6-chlorotryptophan, and in complex with FAD and tryptophan. Partitioning of FAD and tryptophan into different chains of BorH and failure to incorporate tryptophan into AbeH/FAD crystals suggested that flavin and tryptophan binding are negatively coupled in both proteins. ITC and fluorescence quenching experiments confirmed the ability of both AbeH and BorH to form binary complexes with FAD or tryptophan and the inability of tryptophan to bind to AbeH/FAD or BorH/FAD complexes. FAD could not bind to BorH/tryptophan complexes, but FAD appears to displace tryptophan from AbeH/tryptophan complexes in an endothermic entropically-driven process.
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Affiliation(s)
- Md Ashaduzzaman
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - Kazi Lingkon
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - Aravinda J De Silva
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
| | - John J Bellizzi
- Department of Chemistry and Biochemistry, The University of Toledo, Toledo OH 43606
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5
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Jiang Y, Lewis JC. Asymmetric catalysis by flavin-dependent halogenases. Chirality 2023; 35:452-460. [PMID: 36916449 PMCID: PMC11301518 DOI: 10.1002/chir.23550] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 03/16/2023]
Abstract
In nature, flavin-dependent halogenases (FDHs) catalyze site-selective chlorination and bromination of aromatic natural products. This ability has led to extensive efforts to engineer FDHs for selective chlorination, bromination, and iodination of electron rich aromatic compounds. On the other hand, FDHs are unique among halogenases and haloperoxidases that exhibit catalyst-controlled site selectivity in that no examples of enantioselective FDH catalysis in natural product biosynthesis have been characterized. Over the past several years, our group has established that FDHs can catalyze enantioselective reactions involving desymmetrization, atroposelective halogenation, and halocyclization. Achieving high activity and selectivity for these reactions has required extensive mutagenesis and mitigation of problems resulting from hypohalous acid generated during FDH catalysis. The single-component flavin reductase/FDH AetF is unique among the wild type enzyme we have studied in that it provides high activity and selectivity toward several asymmetric transformations. These results highlight the ability of FDH active sites to tolerate different substrate topologies and suggest that they could be useful for a broad range of oxidative halogenations.
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Affiliation(s)
- Yuhua Jiang
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Jared C Lewis
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
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6
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Gäfe S, Niemann HH. Structural basis of regioselective tryptophan dibromination by the single-component flavin-dependent halogenase AetF. Acta Crystallogr D Struct Biol 2023; 79:596-609. [PMID: 37314407 PMCID: PMC10306068 DOI: 10.1107/s2059798323004254] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/15/2023] [Indexed: 06/15/2023] Open
Abstract
The flavin-dependent halogenase (FDH) AetF successively brominates tryptophan at C5 and C7 to generate 5,7-dibromotryptophan. In contrast to the well studied two-component tryptophan halogenases, AetF is a single-component flavoprotein monooxygenase. Here, crystal structures of AetF alone and in complex with various substrates are presented, representing the first experimental structures of a single-component FDH. Rotational pseudosymmetry and pseudomerohedral twinning complicated the phasing of one structure. AetF is structurally related to flavin-dependent monooxygenases. It contains two dinucleotide-binding domains for binding the ADP moiety with unusual sequences that deviate from the consensus sequences GXGXXG and GXGXXA. A large domain tightly binds the cofactor flavin adenine dinucleotide (FAD), while the small domain responsible for binding the nicotinamide adenine dinucleotide (NADP) is unoccupied. About half of the protein forms additional structural elements containing the tryptophan binding site. FAD and tryptophan are about 16 Å apart. A tunnel between them presumably allows diffusion of the active halogenating agent hypohalous acid from FAD to the substrate. Tryptophan and 5-bromotryptophan bind to the same site but with a different binding pose. A flip of the indole moiety identically positions C5 of tryptophan and C7 of 5-bromotryptophan next to the tunnel and to catalytic residues, providing a simple explanation for the regioselectivity of the two successive halogenations. AetF can also bind 7-bromotryptophan in the same orientation as tryptophan. This opens the way for the biocatalytic production of differentially dihalogenated tryptophan derivatives. The structural conservation of a catalytic lysine suggests a way to identify novel single-component FDHs.
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Affiliation(s)
- Simon Gäfe
- Department of Chemistry, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld, Germany
| | - Hartmut H. Niemann
- Department of Chemistry, Bielefeld University, Universitaetsstrasse 25, 33615 Bielefeld, Germany
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7
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Matysik J, Gerhards L, Theiss T, Timmermann L, Kurle-Tucholski P, Musabirova G, Qin R, Ortmann F, Solov'yov IA, Gulder T. Spin Dynamics of Flavoproteins. Int J Mol Sci 2023; 24:ijms24098218. [PMID: 37175925 PMCID: PMC10179055 DOI: 10.3390/ijms24098218] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
This short review reports the surprising phenomenon of nuclear hyperpolarization occurring in chemical reactions, which is called CIDNP (chemically induced dynamic nuclear polarization) or photo-CIDNP if the chemical reaction is light-driven. The phenomenon occurs in both liquid and solid-state, and electron transfer systems, often carrying flavins as electron acceptors, are involved. Here, we explain the physical and chemical properties of flavins, their occurrence in spin-correlated radical pairs (SCRP) and the possible involvement of flavin-carrying SCRPs in animal magneto-reception at earth's magnetic field.
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Affiliation(s)
- Jörg Matysik
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Luca Gerhards
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tobias Theiss
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | - Lisa Timmermann
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
| | | | - Guzel Musabirova
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Ruonan Qin
- Institut für Analytische Chemie, Universität Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
| | - Frank Ortmann
- TUM School of Natural Sciences, Technische Universität München, Lichtenbergstr. 4, 85748 Garching, Germany
| | - Ilia A Solov'yov
- Institut für Physik, Carl von Ossietzky Universität Oldenburg, Carl-von Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Research Center for Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
- Center for Nanoscale Dynamics (CENAD), Carl von Ossietzky Universität Oldenburg, Carl-von-Ossietzky-Str. 9-11, 26129 Oldenburg, Germany
| | - Tanja Gulder
- Institut für Organische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
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8
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Zhai G, Gong R, Lin Y, Zhang M, Li J, Deng Z, Sun J, Chen W, Zhang Z. Structural Insight into the Catalytic Mechanism of Non-Heme Iron Halogenase AdaV in 2′-Chloropentostatin Biosynthesis. ACS Catal 2022. [DOI: 10.1021/acscatal.2c04608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Guoqing Zhai
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Rong Gong
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Yaxin Lin
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Meng Zhang
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Jiahui Li
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Zixin Deng
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Jiazhong Sun
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Wenqing Chen
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Abichem Biotech Joint Center for Pharmaceutical Innovation, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
| | - Zhengyu Zhang
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and School of Pharmaceutical Sciences, Wuhan University, Wuhan 430071, China
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9
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Halogenase-Targeted Genome Mining Leads to the Discovery of (±) Pestalachlorides A1a, A2a, and Their Atropisomers. Antibiotics (Basel) 2022; 11:antibiotics11101304. [PMID: 36289962 PMCID: PMC9598291 DOI: 10.3390/antibiotics11101304] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/14/2022] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Genome mining has become an important tool for discovering new natural products and identifying the cryptic biosynthesis gene clusters. Here, we utilized the flavin-dependent halogenase GedL as the probe in combination with characteristic halogen isotope patterns to mine new halogenated secondary metabolites from our in-house fungal database. As a result, two pairs of atropisomers, pestalachlorides A1a (1a)/A1b (1b) and A2a (2a)/A2b (2b), along with known compounds pestalachloride A (3) and SB87-H (4), were identified from Pestalotiopsis rhododendri LF-19-12. A plausible biosynthetic assembly line for pestalachlorides involving a putative free-standing phenol flavin-dependent halogenase was proposed based on bioinformatics analysis. Pestalachlorides exhibited antibacterial activity against sensitive and drug-resistant S. aureus and E. faecium with MIC values ranging from 4 μg/mL to 32 μg/mL. This study indicates that halogenase-targeted genome mining is an efficient strategy for discovering halogenated compounds and their corresponding halogenases.
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10
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Yin L. Crystal structure determination of the halogenase CtcP from Streptomyces aureofaciens. Acta Crystallogr F Struct Biol Commun 2022; 78:270-275. [PMID: 35787554 PMCID: PMC9254895 DOI: 10.1107/s2053230x22006586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/24/2022] [Indexed: 11/10/2022] Open
Abstract
Chlortetracycline (CTC), a derivative of tetracycline (TC), is a broadly used antibiotic that inhibits the synthesis of bacterial proteins by competing with the A-site tRNA on ribosomes. A recent study showed that during the biosynthesis of CTC in Streptomyces aureofaciens, the halogenase CtcP catalyzes the final chlorination reaction and transforms TC into CTC. However, the structure of this fundamental enzyme is still lacking. Here, selenomethionine-derivatized CtcP from S. aureofaciens was overexpressed and purified and its structure was determined at 2.7 Å resolution. The structure of CtcP reveals the conserved monooxygenase domain shared by all flavin-dependent halogenases and a unique C-terminal domain. Although FAD was not observed in the structure, the monooxygenase domain has a conserved FAD-binding pocket and active center. The C-terminal domain displays an α-helical bundle fold, which could contribute to substrate specificity. This work provides a molecular basis for enzyme engineering to improve the industrial production of CTC.
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Affiliation(s)
- Lijuan Yin
- Department of Pathology, Changhai Hospital, The Second Military Medical University, 168 Changhai Road, Shanghai 200433, People’s Republic of China
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11
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Mechanism-guided tunnel engineering to increase the efficiency of a flavin-dependent halogenase. Nat Catal 2022. [DOI: 10.1038/s41929-022-00800-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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12
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Cheng W, Chen M, Ohashi M, Tang Y. Biosynthesis of Terpenoid-Pyrrolobenzoxazine Hybrid Natural Product CJ-12662. Angew Chem Int Ed Engl 2022; 61:e202116928. [PMID: 35075754 DOI: 10.1002/anie.202116928] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Indexed: 11/11/2022]
Abstract
The fungal natural product CJ-12662 is a structurally complex terpene-amino acid hybrid, and is a potent anthelmintic compound. The biosynthetic pathway of CJ-12662 is elucidated based on metabolite analysis from heterologous expression. We demonstrate the terpene portion is derived from successive P450-catalyzed oxidations of amorpha-4,11-diene, while three flavin-dependent enzymes are involved in morphing the esterified tryptophan into a chlorinated pyrrolobenzoxazine, utilizing a cascaded [1,2]-Meisenheimer rearrangement.
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Affiliation(s)
- Wei Cheng
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.,State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing, 100191, China
| | - Mengbin Chen
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.,Present address: Merck & Co, Inc., Rahway, NJ, USA
| | - Masao Ohashi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, USA.,Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA
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13
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Liu M, Ohashi M, Hung YS, Scherlach K, Watanabe K, Hertweck C, Tang Y. AoiQ Catalyzes Geminal Dichlorination of 1,3-Diketone Natural Products. J Am Chem Soc 2021; 143:7267-7271. [PMID: 33957045 PMCID: PMC8434754 DOI: 10.1021/jacs.1c02868] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Enzymes that can perform halogenation of aliphatic carbons are of significant interest to the synthetic and biocatalysis communities. Here we describe the characterization of AoiQ, a single-component flavin-dependent halogenase (FDH) that catalyzes gem-dichlorination of 1,3-diketone substrates in the biosynthesis of dichlorodiaporthin. AoiQ represents the first biochemically reconstituted FDH that can halogenate an enolizable sp3-hybridized carbon atom.
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Affiliation(s)
- Mengting Liu
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA
- Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030
| | - Masao Ohashi
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA
| | - Yiu-Sun Hung
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA
| | - Kirstin Scherlach
- Leibniz Institute for Natural Product Research and Infection Biology – HKI, 07745 Jena, Germany
| | - Kenji Watanabe
- Department of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan
| | - Christian Hertweck
- Leibniz Institute for Natural Product Research and Infection Biology – HKI, 07745 Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA
- Department of Chemistry and Biochemistry University of California, Los Angeles, California 90095, USA
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14
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Phintha A, Prakinee K, Jaruwat A, Lawan N, Visitsatthawong S, Kantiwiriyawanitch C, Songsungthong W, Trisrivirat D, Chenprakhon P, Mulholland A, van Pée KH, Chitnumsub P, Chaiyen P. Dissecting the low catalytic capability of flavin-dependent halogenases. J Biol Chem 2021; 296:100068. [PMID: 33465708 PMCID: PMC7948982 DOI: 10.1074/jbc.ra120.016004] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/11/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
Although flavin-dependent halogenases (FDHs) are attractive biocatalysts, their practical applications are limited because of their low catalytic efficiency. Here, we investigated the reaction mechanisms and structures of tryptophan 6-halogenase (Thal) from Streptomyces albogriseolus using stopped-flow, rapid-quench flow, quantum/mechanics molecular mechanics calculations, crystallography, and detection of intermediate (hypohalous acid [HOX]) liberation. We found that the key flavin intermediate, C4a-hydroperoxyflavin (C4aOOH-FAD), formed by Thal and other FDHs (tryptophan 7-halogenase [PrnA] and tryptophan 5-halogenase [PyrH]), can react with I-, Br-, and Cl- but not F- to form C4a-hydroxyflavin and HOX. Our experiments revealed that I- reacts with C4aOOH-FAD the fastest with the lowest energy barrier and have shown for the first time that a significant amount of the HOX formed leaks out as free HOX. This leakage is probably a major cause of low product coupling ratios in all FDHs. Site-saturation mutagenesis of Lys79 showed that changing Lys79 to any other amino acid resulted in an inactive enzyme. However, the levels of liberated HOX of these variants are all similar, implying that Lys79 probably does not form a chloramine or bromamine intermediate as previously proposed. Computational calculations revealed that Lys79 has an abnormally lower pKa compared with other Lys residues, implying that the catalytic Lys may act as a proton donor in catalysis. Analysis of new X-ray structures of Thal also explains why premixing of FDHs with reduced flavin adenine dinucleotide generally results in abolishment of C4aOOH-FAD formation. These findings reveal the hidden factors restricting FDHs capability which should be useful for future development of FDHs applications.
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Affiliation(s)
- Aisaraphon Phintha
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Kridsadakorn Prakinee
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Aritsara Jaruwat
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand
| | - Narin Lawan
- Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Surawit Visitsatthawong
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Chadaporn Kantiwiriyawanitch
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Warangkhana Songsungthong
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand
| | - Duangthip Trisrivirat
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand
| | - Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand
| | - Adrian Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol, UK
| | - Karl-Heinz van Pée
- General Biochemistry, Faculty of Chemistry and Food Chemistry, Technical University of Dresden, Dresden, Germany
| | - Penchit Chitnumsub
- Biomolecular Analysis and Application Research Team, National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani, Thailand.
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok, Thailand; School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong, Thailand.
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