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Chen M, Petriti V, Mondal A, Jiang Y, Ding Y. Direct aromatic nitration by bacterial P450 enzymes. Methods Enzymol 2023; 693:307-337. [PMID: 37977734 PMCID: PMC10928822 DOI: 10.1016/bs.mie.2023.09.008] [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] [Indexed: 11/19/2023]
Abstract
Nitro aromatics have broad applications in industry, agriculture, and pharmaceutics. However, their industrial production is faced with many challenges including poor selectivity, heavy pollution and safety concerns. Nature provides multiple strategies for aromatic nitration, which opens the door for the development of green and efficient biocatalysts. Our group's efforts focused on a unique bacterial cytochrome P450 TxtE that originates from the biosynthetic pathway of phytotoxin thaxtomins, which can install a nitro group at C4 of l-Trp indole ring. TxtE is a Class I P450 and its reaction relies on a pair of redox partners ferredoxin and ferredoxin reductase for essential electron transfer. To develop TxtE as an efficient nitration biocatalyst, we created artificial self-sufficient P450 chimeras by fusing TxtE with the reductase domain of the bacterial P450BM3 (BM3R). We evaluated the catalytic performance of the chimeras with different lengths of the linker connecting TxtE and BM3R domains and identified one with a 14-amino-acid linker (TB14) to give the best activity. In addition, we demonstrated the broad substrate scope of the engineered biocatalyst by screening diverse l-Trp analogs. In this chapter, we provide a detailed procedure for the development of aromatic nitration biocatalysts, including the construction of P450 fusion chimeras, biochemical characterization, determination of catalytic parameters, and testing of enzyme-substrate scope. These protocols can be followed to engineer other P450 enzymes and illustrate the processes of biocatalytic development for the synthesis of nitro chemicals.
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Affiliation(s)
- Manyun Chen
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Vanisa Petriti
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Amit Mondal
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Yujia Jiang
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States
| | - Yousong Ding
- Department of Medicinal Chemistry, Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida, Gainesville, FL, United States.
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Wang X, Lin X, Jiang Y, Qin X, Ma N, Yao F, Dong S, Liu C, Feng Y, Jin L, Xian M, Cong Z. Engineering Cytochrome P450BM3 Enzymes for Direct Nitration of Unsaturated Hydrocarbons. Angew Chem Int Ed Engl 2023; 62:e202217678. [PMID: 36660956 DOI: 10.1002/anie.202217678] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
Applications of the peroxidase activity of cytochrome P450 enzymes in synthetic chemistry remain largely unexplored. We present herein a protein engineering strategy to increase cytochrome P450BM3 peroxidase activity for the direct nitration of aromatic compounds and terminal aryl-substituted olefins in the presence of a dual-functional small molecule (DFSM). Site-directed mutations of key active-site residues allowed the efficient regulation of steric effects to limit substrate access and, thus, a significant decrease in monooxygenation activity and increase in peroxidase activity. Nitration of several phenol and aniline compounds also yielded ortho- and para-nitration products with moderate-to-high total turnover numbers. Besides direct aromatic nitration by P450 variants using nitrite as a nitrating agent, we also demonstrated the use of the DFSM-facilitated P450 peroxidase system for the nitration of the vinyl group of styrene and its derivatives.
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Affiliation(s)
- Xiling Wang
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Xiaodan Lin
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiping Jiang
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Xiangquan Qin
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.,Department of Chemistry, Yanbian University Yanji, Jilin, 133002, China
| | - Nana Ma
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fuquan Yao
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Chuanfei Liu
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Longyi Jin
- Department of Chemistry, Yanbian University Yanji, Jilin, 133002, China
| | - Mo Xian
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Zhiqi Cong
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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Nóbile ML, Stricker AM, Marchesano L, Iribarren AM, Lewkowicz ES. N-oxygenation of amino compounds: Early stages in its application to the biocatalyzed preparation of bioactive compounds. Biotechnol Adv 2021; 51:107726. [PMID: 33675955 DOI: 10.1016/j.biotechadv.2021.107726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 10/22/2022]
Abstract
Among the compounds that contain unusual functional groups, nitro is perhaps one of the most interesting due to the valuable properties it confers on pharmaceuticals and explosives. Traditional chemistry has for many years used environmentally unfriendly strategies; in contrast, the biocatalyzed production of this type of products offers a promising alternative. The small family of enzymes formed by N-oxygenases allows the conversion of an amino group to a nitro through the sequential addition of oxygen. These enzymes also make it possible to obtain other less oxidized N-O functions, such as hydroxylamine or nitroso, present in intermediate or final products. The current substrates on which these enzymes are reported to work encompass a few aromatic molecules and sugars. The unique characteristics of N-oxygenases and the great economic value of the products that they could generate, place them in a position of very high scientific and industrial interest. The most important and best studied N-oxygenases will be presented here.
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Affiliation(s)
- Matías L Nóbile
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina.
| | - Abigail M Stricker
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Lucas Marchesano
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Adolfo M Iribarren
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Elizabeth S Lewkowicz
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
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Wei W, Siegbahn PEM, Liao R. Mechanism of the Dinuclear Iron Enzymep‐Aminobenzoate N‐oxygenase from Density Functional Calculations. ChemCatChem 2018. [DOI: 10.1002/cctc.201801072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wen‐Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
| | - Per E. M. Siegbahn
- Department of Organic Chemistry, Arrhenius LaboratoryStockholm University Stockholm SE-10691 Sweden
| | - Rong‐Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of Education Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica Hubei Key Laboratory of Materials Chemistry and Service Failure School of Chemistry and Chemical EngineeringHuazhong University of Science and Technology Wuhan 430074 P. R. China
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Komor AJ, Jasniewski AJ, Que L, Lipscomb JD. Diiron monooxygenases in natural product biosynthesis. Nat Prod Rep 2018; 35:646-659. [PMID: 29552683 PMCID: PMC6051903 DOI: 10.1039/c7np00061h] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: up to 2017 The participation of non-heme dinuclear iron cluster-containing monooxygenases in natural product biosynthetic pathways has been recognized only recently. At present, two families have been discovered. The archetypal member of the first family, CmlA, catalyzes β-hydroxylation of l-p-aminophenylalanine (l-PAPA) covalently linked to the nonribosomal peptide synthetase (NRPS) CmlP, thereby effecting the first step in the biosynthesis of chloramphenicol by Streptomyces venezuelae. CmlA houses the diiron cluster in a metallo-β-lactamase protein fold instead of the 4-helix bundle fold of nearly every other diiron monooxygenase. CmlA couples O2 activation and substrate hydroxylation via a structural change caused by formation of the l-PAPA-loaded CmlP:CmlA complex. The other new diiron family is typified by two enzymes, AurF and CmlI, which catalyze conversion of aryl-amine substrates to aryl-nitro products with incorporation of oxygen from O2. AurF from Streptomyces thioluteus catalyzes the formation of p-nitrobenzoate from p-aminobenzoate as a precursor to the biostatic compound aureothin, whereas CmlI from S. venezuelae catalyzes the ultimate aryl-amine to aryl-nitro step in chloramphenicol biosynthesis. Both enzymes stabilize a novel type of peroxo-intermediate as the reactive species. The rare 6-electron N-oxygenation reactions of CmlI and AurF involve two progressively oxidized pathway intermediates. The enzymes optimize efficiency by utilizing one of the reaction pathway intermediates as an in situ reductant for the diiron cluster, while simultaneously generating the next pathway intermediate. For CmlI, this reduction allows mid-pathway regeneration of the peroxo intermediate required to complete the biosynthesis. CmlI ensures specificity by carrying out the multistep aryl-amine oxygenation without dissociating intermediate products.
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Affiliation(s)
- Anna J Komor
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - Andrew J Jasniewski
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
| | - John D Lipscomb
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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Waldman AJ, Ng TL, Wang P, Balskus EP. Heteroatom-Heteroatom Bond Formation in Natural Product Biosynthesis. Chem Rev 2017; 117:5784-5863. [PMID: 28375000 PMCID: PMC5534343 DOI: 10.1021/acs.chemrev.6b00621] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Natural products that contain functional groups with heteroatom-heteroatom linkages (X-X, where X = N, O, S, and P) are a small yet intriguing group of metabolites. The reactivity and diversity of these structural motifs has captured the interest of synthetic and biological chemists alike. Functional groups containing X-X bonds are found in all major classes of natural products and often impart significant biological activity. This review presents our current understanding of the biosynthetic logic and enzymatic chemistry involved in the construction of X-X bond containing functional groups within natural products. Elucidating and characterizing biosynthetic pathways that generate X-X bonds could both provide tools for biocatalysis and synthetic biology, as well as guide efforts to uncover new natural products containing these structural features.
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Affiliation(s)
- Abraham J. Waldman
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Tai L. Ng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Peng Wang
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
| | - Emily P. Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States
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Knoot CJ, Kovaleva EG, Lipscomb JD. Crystal structure of CmlI, the arylamine oxygenase from the chloramphenicol biosynthetic pathway. J Biol Inorg Chem 2016; 21:589-603. [PMID: 27229511 PMCID: PMC4994471 DOI: 10.1007/s00775-016-1363-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 05/16/2016] [Indexed: 11/28/2022]
Abstract
The diiron cluster-containing oxygenase CmlI catalyzes the conversion of the aromatic amine precursor of chloramphenicol to the nitroaromatic moiety of the active antibiotic. The X-ray crystal structures of the fully active, N-terminally truncated CmlIΔ33 in the chemically reduced Fe(2+)/Fe(2+) state and a cis μ-1,2(η (1):η (1))-peroxo complex are presented. These structures allow comparison with the homologous arylamine oxygenase AurF as well as other types of diiron cluster-containing oxygenases. The structural model of CmlIΔ33 crystallized at pH 6.8 lacks the oxo-bridge apparent from the enzyme optical spectrum in solution at higher pH. In its place, residue E236 forms a μ-1,3(η (1):η (2)) bridge between the irons in both models. This orientation of E236 stabilizes a helical region near the cluster which closes the active site to substrate binding in contrast to the open site found for AurF. A very similar closed structure was observed for the inactive dimanganese form of AurF. The observation of this same structure in different arylamine oxygenases may indicate that there are two structural states that are involved in regulation of the catalytic cycle. Both the structural studies and single crystal optical spectra indicate that the observed cis μ-1,2(η (1):η (1))-peroxo complex differs from the μ-η (1):η (2)-peroxo proposed from spectroscopic studies of a reactive intermediate formed in solution by addition of O2 to diferrous CmlI. It is proposed that the structural changes required to open the active site also drive conversion of the µ-1,2-peroxo species to the reactive form.
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Affiliation(s)
- Cory J Knoot
- Department of Biochemistry Molecular Biology and Biophysics and the Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Elena G Kovaleva
- Stanford Synchrotron Radiation Lightsource, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | - John D Lipscomb
- Department of Biochemistry Molecular Biology and Biophysics and the Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN, 55455, USA.
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Komor AJ, Rivard BS, Fan R, Guo Y, Que L, Lipscomb JD. Mechanism for Six-Electron Aryl-N-Oxygenation by the Non-Heme Diiron Enzyme CmlI. J Am Chem Soc 2016; 138:7411-21. [PMID: 27203126 PMCID: PMC4914076 DOI: 10.1021/jacs.6b03341] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The ultimate step in chloramphenicol (CAM) biosynthesis is a six-electron oxidation of an aryl-amine precursor (NH2-CAM) to the aryl-nitro group of CAM catalyzed by the non-heme diiron cluster-containing oxygenase CmlI. Upon exposure of the diferrous cluster to O2, CmlI forms a long-lived peroxo intermediate, P, which reacts with NH2-CAM to form CAM. Since P is capable of at most a two-electron oxidation, the overall reaction must occur in several steps. It is unknown whether P is the oxidant in each step or whether another oxidizing species participates in the reaction. Mass spectrometry product analysis of reactions under (18)O2 show that both oxygen atoms in the nitro function of CAM derive from O2. However, when the single-turnover reaction between (18)O2-P and NH2-CAM is carried out in an (16)O2 atmosphere, CAM nitro groups contain both (18)O and (16)O, suggesting that P can be reformed during the reaction sequence. Such reformation would require reduction by a pathway intermediate, shown here to be NH(OH)-CAM. Accordingly, the aerobic reaction of NH(OH)-CAM with diferric CmlI yields P and then CAM without an external reductant. A catalytic cycle is proposed in which NH2-CAM reacts with P to form NH(OH)-CAM and diferric CmlI. Then the NH(OH)-CAM rereduces the enzyme diiron cluster, allowing P to reform upon O2 binding, while itself being oxidized to NO-CAM. Finally, the reformed P oxidizes NO-CAM to CAM with incorporation of a second O2-derived oxygen atom. The complete six-electron oxidation requires only two exogenous electrons and could occur in one active site.
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Affiliation(s)
- Anna J. Komor
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - Brent S. Rivard
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Ruixi Fan
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Lawrence Que
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
| | - John D. Lipscomb
- Center for Metals in Biocatalysis, University of Minnesota, Minneapolis, MN 55455
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Zuo R, Zhang Y, Huguet‐Tapia JC, Mehta M, Dedic E, Bruner SD, Loria R, Ding Y. An artificial self‐sufficient cytochrome P450 directly nitrates fluorinated tryptophan analogs with a different regio‐selectivity. Biotechnol J 2016; 11:624-32. [DOI: 10.1002/biot.201500416] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 11/16/2015] [Accepted: 12/23/2015] [Indexed: 11/07/2022]
Affiliation(s)
- Ran Zuo
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville Florida USA
| | - Yi Zhang
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville Florida USA
| | - Jose C. Huguet‐Tapia
- Department of Plant Pathology, Institute of Food and Agricultural Sciences, University of Florida Gainesville Florida USA
| | - Mishal Mehta
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville Florida USA
| | - Evelina Dedic
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville Florida USA
| | - Steven D. Bruner
- Department of Chemistry, University of Florida Gainesville Florida USA
- Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida Gainesville Florida USA
| | - Rosemary Loria
- Department of Plant Pathology, Institute of Food and Agricultural Sciences, University of Florida Gainesville Florida USA
| | - Yousong Ding
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida Gainesville Florida USA
- Center for Natural Products, Drug Discovery and Development, College of Pharmacy, University of Florida Gainesville Florida USA
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Indest KJ, Eberly JO, Hancock DE. Expression and characterization of an N-oxygenase from Rhodococcus jostii RHAI. J GEN APPL MICROBIOL 2015; 61:217-23. [DOI: 10.2323/jgam.61.217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Karl J. Indest
- U.S. Army Engineer Research and Development Center, Environmental Laboratory
| | - Jed O. Eberly
- U.S. Army Engineer Research and Development Center, Environmental Laboratory
| | - Dawn E. Hancock
- U.S. Army Engineer Research and Development Center, Environmental Laboratory
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Characterization of the N-oxygenase AurF from Streptomyces thioletus. Bioorg Med Chem 2014; 22:5569-77. [PMID: 24973817 DOI: 10.1016/j.bmc.2014.06.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/29/2014] [Accepted: 06/01/2014] [Indexed: 11/21/2022]
Abstract
AurF catalyzes the N-oxidation of p-aminobenzoic acid to p-nitrobenzoic acid in the biosynthesis of the antibiotic aureothin. Here we report the characterization of AurF under optimized conditions to explore its potential use in biocatalysis. The pH optimum of the enzyme was established to be 5.5 using phenazine methosulfate (PMS)/NADH as the enzyme mediator system, showing ~10-fold higher activity than previous reports in literature. Kinetic characterization at optimized conditions give a Km of 14.7 ± 1.1 μM, a kcat of 47.5 ± 5.4 min(-1) and a kcat/Km of 3.2 ± 0.4 μM(-1)min(-1). PMS/NADH and the native electron transfer proteins showed significant formation of the p-hydroxylaminobenzoic acid intermediate, however H2O2 produced mostly p-nitrobenzoic acid. Alanine scanning identified the role of important active site residues. The substrate specificity of AurF was examined and rationalized based on the protein crystal structure. Kinetic studies indicate that the Km is the main determinant of AurF activity toward alternative substrates.
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Fries A, Bretschneider T, Winkler R, Hertweck C. A ribonucleotide reductase-like electron transfer system in the nitroaryl-forming N-oxygenase AurF. Chembiochem 2011; 12:1832-5. [PMID: 21678538 DOI: 10.1002/cbic.201100138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Alexander Fries
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Beutenbergstrasse 11a, 07745 Jena, Germany
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Cortina NS, Revermann O, Krug D, Müller R. Identification and Characterization of the Althiomycin Biosynthetic Gene Cluster in Myxococcus xanthus DK897. Chembiochem 2011; 12:1411-6. [DOI: 10.1002/cbic.201100154] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Indexed: 11/06/2022]
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Li N, Korboukh VK, Krebs C, Bollinger JM. Four-electron oxidation of p-hydroxylaminobenzoate to p-nitrobenzoate by a peroxodiferric complex in AurF from Streptomyces thioluteus. Proc Natl Acad Sci U S A 2010; 107:15722-7. [PMID: 20798054 PMCID: PMC2936605 DOI: 10.1073/pnas.1002785107] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nonheme di-iron oxygenase, AurF, converts p-aminobenzoate (Ar-NH(2), where Ar = 4-carboxyphenyl) to p-nitrobenzoate (Ar-NO(2)) in the biosynthesis of the antibiotic, aureothin, by Streptomyces thioluteus. It has been reported that this net six-electron oxidation proceeds in three consecutive, two-electron steps, through p-hydroxylaminobenzoate (Ar-NHOH) and p-nitrosobenzoate (Ar-NO) intermediates, with each step requiring one equivalent of O(2) and two exogenous reducing equivalents. We recently demonstrated that a peroxodiiron(III/III) complex (peroxo- -AurF) formed by addition of O(2) to the diiron(II/II) enzyme ( -AurF) effects the initial oxidation of Ar-NH(2), generating a mu-(oxo)diiron(III/III) form of the enzyme (mu-oxo- -AurF) and (presumably) Ar-NHOH. Here we show that peroxo- -AurF also oxidizes Ar-NHOH. Unexpectedly, this reaction proceeds through to the Ar-NO(2) final product, a four-electron oxidation, and produces -AurF, with which O(2) can combine to regenerate peroxo- -AurF. Thus, conversion of Ar-NHOH to Ar-NO(2) requires only a single equivalent of O(2) and (starting from -AurF or peroxo- -AurF) is fully catalytic in the absence of exogenous reducing equivalents, by contrast to the published stoichiometry. This novel type of four-electron N-oxidation is likely also to occur in the reaction sequences of nitro-installing di-iron amine oxygenases in the biosyntheses of other natural products.
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Affiliation(s)
- Ning Li
- Departments of Biochemistry and Molecular Biology and
| | - Victoria Korneeva Korboukh
- Departments of Biochemistry and Molecular Biology and
- Chemistry, Pennsylvania State University, University Park, PA 16802
| | - Carsten Krebs
- Departments of Biochemistry and Molecular Biology and
- Chemistry, Pennsylvania State University, University Park, PA 16802
| | - J. Martin Bollinger
- Departments of Biochemistry and Molecular Biology and
- Chemistry, Pennsylvania State University, University Park, PA 16802
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Fries A, Winkler R, Hertweck C. Structural and biochemical basis for the firm chemo- and regioselectivity of the nitro-forming N-oxygenase AurF. Chem Commun (Camb) 2010; 46:7760-2. [DOI: 10.1039/c0cc02811h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Korboukh VK, Li N, Barr EW, Bollinger JM, Krebs C. A long-lived, substrate-hydroxylating peroxodiiron(III/III) intermediate in the amine oxygenase, AurF, from Streptomyces thioluteus. J Am Chem Soc 2009; 131:13608-9. [PMID: 19731912 DOI: 10.1021/ja9064969] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The amine oxygenase AurF from Streptomyces thioluteus catalyzes the six-electron oxidation of p-aminobenzoate (pABA) to p-nitrobenzoate (pNBA). In this work, we have studied the reaction of its reduced Fe(2)(II/II) cofactor with O(2), which results in generation of a peroxo-Fe(2)(III/III) intermediate. In the absence of substrate, this intermediate is unusually stable (t(1/2) = 7 min at 20 degrees C), allowing for its accumulation to almost stoichiometric amounts. Its decay is accelerated approximately 10(5)-fold by the substrate, pABA, implying that it is the complex that effects the two-electron oxidation of the amine to the hydroxylamine. The nearly quantitative conversion of pABA to pNBA by solutions containing an excess of the intermediate suggests that it may also be competent for the two subsequent two-electron oxidations leading to the product.
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Busch B, Hertweck C. Evolution of metabolic diversity in polyketide-derived pyrones: using the non-colinear aureothin assembly line as a model system. PHYTOCHEMISTRY 2009; 70:1833-1840. [PMID: 19651421 DOI: 10.1016/j.phytochem.2009.05.022] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 05/26/2009] [Accepted: 05/27/2009] [Indexed: 05/28/2023]
Abstract
Polyketide-derived pyrones are structurally diverse secondary metabolites that are represented in all three kingdoms of life and are endowed with various biological functions. The aureothin family of Streptomyces metabolites was chosen as a model to study the factors governing structural diversity and the evolutionary processes involved. This review highlights recent insights into the non-colinear aureothin and neoaureothin modular type I polyketide synthase (PKS), aromatic starter unit biosynthesis, polyketide tailoring reactions, and a non-enzymatic polyene splicing cascade. Pyrone biosynthesis in bacteria, fungi, and plants is compared. Finally, various strategies to increase metabolic diversity of aureothin derivatives through mutasynthesis, pathway engineering, and biotransformation are presented. The unusual aureothin and neoaureothin assembly lines thus not only represent a model for PKS evolution, but provided important insights into non-canonical enzymatic processes that could be employed for the production of antitumor and antifungal agents.
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Affiliation(s)
- Benjamin Busch
- Leibniz Institute for Natural Product Research and Infection Biology, HKI, Department of Biomolecular Chemistry, Jena, Germany
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Wackett LP. Questioning our perceptions about evolution of biodegradative enzymes. Curr Opin Microbiol 2009; 12:244-51. [DOI: 10.1016/j.mib.2009.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 05/02/2009] [Accepted: 05/05/2009] [Indexed: 10/20/2022]
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Roth A, Plass W. Carboxylate-Bridged Dinuclear Active Sites in Oxygenases: Diiron, Dimanganese, or is Heterodinuclear Better? Angew Chem Int Ed Engl 2008; 47:7588-91. [DOI: 10.1002/anie.200802366] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Roth A, Plass W. Carboxylatverbrückte Zweikernzentren in Oxygenasen: Dieisen, Dimangan oder doch besser heterozweikernig? Angew Chem Int Ed Engl 2008. [DOI: 10.1002/ange.200802366] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Werneburg M, Hertweck C. Chemoenzymatic Total Synthesis of the Antiproliferative Polyketide (+)-(R)-Aureothin. Chembiochem 2008; 9:2064-6. [DOI: 10.1002/cbic.200800301] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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In vitro reconstitution and crystal structure of p-aminobenzoate N-oxygenase (AurF) involved in aureothin biosynthesis. Proc Natl Acad Sci U S A 2008; 105:6858-63. [PMID: 18458342 DOI: 10.1073/pnas.0712073105] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
p-Aminobenzoate N-oxygenase (AurF) from Streptomyces thioluteus catalyzes the formation of unusual polyketide synthase starter unit p-nitrobenzoic acid (pNBA) from p-aminobenzoic acid (pABA) in the biosynthesis of antibiotic aureothin. AurF is a metalloenzyme, but its native enzymatic activity has not been demonstrated in vitro, and its catalytic mechanism is unclear. In addition, the nature of the cofactor remains a controversy. Here, we report the in vitro reconstitution of the AurF enzyme activity, the crystal structure of AurF in the oxidized state, and the cocrystal structure of AurF with its product pNBA. Our combined biochemical and structural analysis unequivocally indicates that AurF is a non-heme di-iron monooxygenase that catalyzes sequential oxidation of aminoarenes to nitroarenes via hydroxylamine and nitroso intermediates.
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