1
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Johnson S, Li H, Valentino H, Sobrado P. Mechanism of Nitrone Formation by a Flavin-Dependent Monooxygenase. Biochemistry 2024; 63:1445-1459. [PMID: 38779817 PMCID: PMC11154958 DOI: 10.1021/acs.biochem.3c00656] [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: 11/21/2023] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024]
Abstract
OxaD is a flavin-dependent monooxygenase (FMO) responsible for catalyzing the oxidation of an indole nitrogen atom, resulting in the formation of a nitrone. Nitrones serve as versatile intermediates in complex syntheses, including challenging reactions like cycloadditions. Traditional organic synthesis methods often yield limited results and involve environmentally harmful chemicals. Therefore, the enzymatic synthesis of nitrone-containing compounds holds promise for more sustainable industrial processes. In this study, we explored the catalytic mechanism of OxaD using a combination of steady-state and rapid-reaction kinetics, site-directed mutagenesis, spectroscopy, and structural modeling. Our investigations showed that OxaD catalyzes two oxidations of the indole nitrogen of roquefortine C, ultimately yielding roquefortine L. The reductive-half reaction analysis indicated that OxaD rapidly undergoes reduction and follows a "cautious" flavin reduction mechanism by requiring substrate binding before reduction can take place. This characteristic places OxaD in class A of the FMO family, a classification supported by a structural model featuring a single Rossmann nucleotide binding domain and a glutathione reductase fold. Furthermore, our spectroscopic analysis unveiled both enzyme-substrate and enzyme-intermediate complexes. Our analysis of the oxidative-half reaction suggests that the flavin dehydration step is the slow step in the catalytic cycle. Finally, through mutagenesis of the conserved D63 residue, we demonstrated its role in flavin motion and product oxygenation. Based on our findings, we propose a catalytic mechanism for OxaD and provide insights into the active site architecture within class A FMOs.
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Affiliation(s)
- Sydney
B. Johnson
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hao Li
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Hannah Valentino
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
| | - Pablo Sobrado
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United
States
- Center
of Drug Discovery, Virginia Tech, Blacksburg, Virginia 24061, United
States
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2
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Launay R, Chobert SC, Abby SS, Pierrel F, André I, Esque J. Structural Reconstruction of E. coli Ubi Metabolon Using an AlphaFold2-Based Computational Framework. J Chem Inf Model 2024. [PMID: 38710096 DOI: 10.1021/acs.jcim.4c00304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Ubiquinone (UQ) is a redox polyisoprenoid lipid found in the membranes of bacteria and eukaryotes that has important roles, notably one in respiratory metabolism, which sustains cellular bioenergetics. In Escherichia coli, several steps of the UQ biosynthesis take place in the cytosol. To perform these reactions, a supramolecular assembly called Ubi metabolon is involved. This latter is composed of seven proteins (UbiE, UbiG, UbiF, UbiH, UbiI, UbiJ, and UbiK), and its structural organization is unknown as well as its protein stoichiometry. In this study, a computational framework has been designed to predict the structure of this macromolecular assembly. In several successive steps, we explored the possible protein interactions as well as the protein stoichiometry, to finally obtain a structural organization of the complex. The use of AlphaFold2-based methods combined with evolutionary information enabled us to predict several models whose quality and confidence were further analyzed using different metrics and scores. Our work led to the identification of a "core assembly" that will guide functional and structural characterization of the Ubi metabolon.
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Affiliation(s)
- Romain Launay
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
| | - Sophie-Carole Chobert
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Sophie S Abby
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Fabien Pierrel
- Univ. Grenoble Alpes, CNRS, UMR 5525, VetAgro Sup, Grenoble INP, TIMC, 38000 Grenoble, France
| | - Isabelle André
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
| | - Jérémy Esque
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, 31077 Toulouse, France
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3
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Ouyang X, Liu G, Guo L, Wu G, Xu P, Zhao YL, Tang H. A multifunctional flavoprotein monooxygenase HspB for hydroxylation and C-C cleavage of 6-hydroxy-3-succinoyl-pyridine. Appl Environ Microbiol 2024; 90:e0225523. [PMID: 38415602 PMCID: PMC10952382 DOI: 10.1128/aem.02255-23] [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: 12/14/2023] [Accepted: 01/26/2024] [Indexed: 02/29/2024] Open
Abstract
Flavoprotein monooxygenases catalyze reactions, including hydroxylation and epoxidation, involved in the catabolism, detoxification, and biosynthesis of natural substrates and industrial contaminants. Among them, the 6-hydroxy-3-succinoyl-pyridine (HSP) monooxygenase (HspB) from Pseudomonas putida S16 facilitates the hydroxylation and C-C bond cleavage of the pyridine ring in nicotine. However, the mechanism for biodegradation remains elusive. Here, we refined the crystal structure of HspB and elucidated the detailed mechanism behind the oxidative hydroxylation and C-C cleavage processes. Leveraging structural information about domains for binding the cofactor flavin adenine dinucleotide (FAD) and HSP substrate, we used molecular dynamics simulations and quantum/molecular mechanics calculations to demonstrate that the transfer of an oxygen atom from the reactive FAD peroxide species (C4a-hydroperoxyflavin) to the C3 atom in the HSP substrate constitutes a rate-limiting step, with a calculated reaction barrier of about 20 kcal/mol. Subsequently, the hydrogen atom was rebounded to the FAD cofactor, forming C4a-hydroxyflavin. The residue Cys218 then catalyzed the subsequent hydrolytic process of C-C cleavage. Our findings contribute to a deeper understanding of the versatile functions of flavoproteins in the natural transformation of pyridine and HspB in nicotine degradation.IMPORTANCEPseudomonas putida S16 plays a pivotal role in degrading nicotine, a toxic pyridine derivative that poses significant environmental challenges. This study highlights a key enzyme, HspB (6-hydroxy-3-succinoyl-pyridine monooxygenase), in breaking down nicotine through the pyrrolidine pathway. Utilizing dioxygen and a flavin adenine dinucleotide cofactor, HspB hydroxylates and cleaves the substrate's side chain. Structural analysis of the refined HspB crystal structure, combined with state-of-the-art computations, reveals its distinctive mechanism. The crucial function of Cys218 was never discovered in its homologous enzymes. Our findings not only deepen our understanding of bacterial nicotine degradation but also open avenues for applications in both environmental cleanup and pharmaceutical development.
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Affiliation(s)
- Xingyu Ouyang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Gongquan Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Lihua Guo
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Geng Wu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yi-Lei Zhao
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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4
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Chen L, Champramary S, Sahu N, Indic B, Szűcs A, Nagy G, Maróti G, Pap B, Languar O, Vágvölgyi C, Nagy LG, Kredics L, Sipos G. Dual RNA-Seq Profiling Unveils Mycoparasitic Activities of Trichoderma atroviride against Haploid Armillaria ostoyae in Antagonistic Interaction Assays. Microbiol Spectr 2023; 11:e0462622. [PMID: 37140425 PMCID: PMC10269595 DOI: 10.1128/spectrum.04626-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Armillaria ostoyae, a species among the destructive forest pathogens from the genus Armillaria, causes root rot disease on woody plants worldwide. Efficient control measures to limit the growth and impact of this severe underground pathogen are under investigation. In a previous study, a new soilborne fungal isolate, Trichoderma atroviride SZMC 24276 (TA), exhibited high antagonistic efficacy, which suggested that it could be utilized as a biocontrol agent. The dual culture assay results indicated that the haploid A. ostoyae-derivative SZMC 23085 (AO) (C18/9) is highly susceptible to the mycelial invasion of TA. In the present study, we analyzed the transcriptome of AO and that of TA in in vitro dual culture assays to test the molecular arsenal of Trichoderma antagonism and the defense mechanisms of Armillaria. We conducted time-course analysis and functional annotation and analyzed enriched pathways and differentially expressed genes including biocontrol-related candidate genes from TA and defense-related candidate genes from AO. The results indicated that TA deployed several biocontrol mechanisms when confronted with AO. In response, AO initiated multiple defense mechanisms to protect against the fungal attack. To our knowledge, the present study offers the first transcriptome analysis of a biocontrol fungus attacking AO. Overall, this study provides insights that aid the further exploration of plant pathogen-biocontrol agent interaction mechanisms. IMPORTANCE Armillaria species can survive for decades in the soil on dead woody debris, develop rapidly under favorable conditions, and harmfully infect newly planted forests. Our previous study found Trichoderma atroviride to be highly effective in controlling Armillaria growth; therefore, our current work explored the molecular mechanisms that might play a key role in Trichoderma-Armillaria interactions. Direct confrontation assays combined with time course-based dual transcriptome analysis provided a reliable system for uncovering the interactive molecular dynamics between the fungal plant pathogen and its mycoparasitic partner. Furthermore, using a haploid Armillaria isolate allowed us to survey the deadly prey-invading activities of the mycoparasite and the ultimate defensive strategies of its prey. Our current study provides detailed insights into the essential genes and mechanisms involved in Armillaria defense against Trichoderma and the genes potentially involved in the efficiency of Trichoderma to control Armillaria. In addition, using a sensitive haploid Armillaria strain (C18/9), with its complete genome data already available, also offers the opportunity to test possible variable molecular responses of Armillaria ostoyae toward diverse Trichoderma isolates with various biocontrol abilities. Initial molecular tests of the dual interactions may soon help to develop a targeted biocontrol intervention with mycoparasites against plant pathogens.
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Affiliation(s)
- Liqiong Chen
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Simang Champramary
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Functional Genomics and Bioinformatics Group, Institute of Forest and Natural Resource Management, Faculty of Forestry, University of Sopron, Sopron, Hungary
| | - Neha Sahu
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, Hungary
| | - Boris Indic
- Functional Genomics and Bioinformatics Group, Institute of Forest and Natural Resource Management, Faculty of Forestry, University of Sopron, Sopron, Hungary
| | - Attila Szűcs
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Gábor Nagy
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | | | - Bernadett Pap
- Institute of Plant Biology, Biological Research Center, Szeged, Hungary
| | - Omar Languar
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
- Functional Genomics and Bioinformatics Group, Institute of Forest and Natural Resource Management, Faculty of Forestry, University of Sopron, Sopron, Hungary
| | - Csaba Vágvölgyi
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - László G. Nagy
- Synthetic and Systems Biology Unit, Biological Research Center, Szeged, Hungary
| | - László Kredics
- Department of Microbiology, Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - György Sipos
- Functional Genomics and Bioinformatics Group, Institute of Forest and Natural Resource Management, Faculty of Forestry, University of Sopron, Sopron, Hungary
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5
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Feng KN, Zhang Y, Zhang M, Yang YL, Liu JK, Pan L, Zeng Y. A flavin-monooxygenase catalyzing oxepinone formation and the complete biosynthesis of vibralactone. Nat Commun 2023; 14:3436. [PMID: 37301868 PMCID: PMC10257657 DOI: 10.1038/s41467-023-39108-x] [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: 09/02/2022] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Oxepinone rings represent one of structurally unusual motifs of natural products and the biosynthesis of oxepinones is not fully understood. 1,5-Seco-vibralactone (3) features an oxepinone motif and is a stable metabolite isolated from mycelial cultures of the mushroom Boreostereum vibrans. Cyclization of 3 forms vibralactone (1) whose β-lactone-fused bicyclic core originates from 4-hydroxybenzoate, yet it remains elusive how 4-hydroxybenzoate is converted to 3 especially for the oxepinone ring construction in the biosynthesis of 1. In this work, using activity-guided fractionation together with proteomic analyses, we identify an NADPH/FAD-dependent monooxygenase VibO as the key enzyme performing a crucial ring-expansive oxygenation on the phenol ring to generate the oxepin-2-one structure of 3. The crystal structure of VibO reveals that it forms a dimeric phenol hydroxylase-like architecture featured with a unique substrate-binding pocket adjacent to the bound FAD. Computational modeling and solution studies provide insight into the likely VibO active site geometry, and suggest possible involvement of a flavin-C4a-OO(H) intermediate.
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Affiliation(s)
- Ke-Na Feng
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Yue Zhang
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Mingfang Zhang
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Yan-Long Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, China
| | - Ji-Kai Liu
- School of Pharmaceutical Sciences, South-Central Minzu University, Wuhan, 430074, China
| | - Lifeng Pan
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032, China.
| | - Ying Zeng
- State Key Laboratory of Phytochemistry and Plant Resources in West China and Yunnan Key Laboratory of Natural Medicinal Chemistry, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
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6
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Bilgi M, Peksel A. Induction of Phenol Hydroxylase from
Aspergillus niger
and Its Optimization. ChemistrySelect 2022. [DOI: 10.1002/slct.202103838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Mesut Bilgi
- Department of Chemistry Yildiz Technical University Davutpasa Campus 34220 Davutpasa Istanbul Turkey
| | - Aysegul Peksel
- Department of Chemistry Yildiz Technical University Davutpasa Campus 34220 Davutpasa Istanbul Turkey
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7
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Toplak M, Saleem-Batcha R, Piel J, Teufel R. Catalytic Control of Spiroketal Formation in Rubromycin Polyketide Biosynthesis. Angew Chem Int Ed Engl 2021; 60:26960-26970. [PMID: 34652045 PMCID: PMC9299503 DOI: 10.1002/anie.202109384] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/07/2021] [Indexed: 12/14/2022]
Abstract
The medically important bacterial aromatic polyketide natural products typically feature a planar, polycyclic core structure. An exception is found for the rubromycins, whose backbones are disrupted by a bisbenzannulated [5,6]‐spiroketal pharmacophore that was recently shown to be assembled by flavin‐dependent enzymes. In particular, a flavoprotein monooxygenase proved critical for the drastic oxidative rearrangement of a pentangular precursor and the installment of an intermediate [6,6]‐spiroketal moiety. Here we provide structural and mechanistic insights into the control of catalysis by this spiroketal synthase, which fulfills several important functions as reductase, monooxygenase, and presumably oxidase. The enzyme hereby tightly controls the redox state of the substrate to counteract shunt product formation, while also steering the cleavage of three carbon‐carbon bonds. Our work illustrates an exceptional strategy for the biosynthesis of stable chroman spiroketals.
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Affiliation(s)
- Marina Toplak
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Raspudin Saleem-Batcha
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstr. 25, 79104, Freiburg, Germany
| | - Jörn Piel
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zürich, 8093, Zürich, Switzerland
| | - Robin Teufel
- Faculty of Biology, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
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8
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Toplak M, Saleem‐Batcha R, Piel J, Teufel R. Catalytic Control of Spiroketal Formation in Rubromycin Polyketide Biosynthesis. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202109384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Marina Toplak
- Faculty of Biology University of Freiburg Schänzlestrasse 1 79104 Freiburg Germany
| | - Raspudin Saleem‐Batcha
- Institute of Pharmaceutical Sciences University of Freiburg Albertstr. 25 79104 Freiburg Germany
| | - Jörn Piel
- Institute of Microbiology Eidgenössische Technische Hochschule (ETH) Zürich 8093 Zürich Switzerland
| | - Robin Teufel
- Faculty of Biology University of Freiburg Schänzlestrasse 1 79104 Freiburg Germany
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9
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Lahham M, Jha S, Goj D, Macheroux P, Wallner S. The family of sarcosine oxidases: Same reaction, different products. Arch Biochem Biophys 2021; 704:108868. [PMID: 33812916 DOI: 10.1016/j.abb.2021.108868] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 12/11/2022]
Abstract
The subfamily of sarcosine oxidase is a set of enzymes within the larger family of amine oxidases. It is ubiquitously distributed among different kingdoms of life. The member enzymes catalyze the oxidization of an N-methyl amine bond of amino acids to yield unstable imine species that undergo subsequent spontaneous non-enzymatic reactions, forming an array of different products. These products range from demethylated simple species to complex alkaloids. The enzymes belonging to the sarcosine oxidase family, namely, monomeric and heterotetrameric sarcosine oxidase, l-pipecolate oxidase, N-methyltryptophan oxidase, NikD, l-proline dehydrogenase, FsqB, fructosamine oxidase and saccharopine oxidase have unique features differentiating them from other amine oxidases. This review highlights the key attributes of the sarcosine oxidase family enzymes, in terms of their substrate binding motif, type of oxidation reaction mediated and FAD regeneration, to define the boundaries of this group and demarcate these enzymes from other amine oxidase families.
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Affiliation(s)
- Majd Lahham
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria; Department of Biochemistry and Microbiology, Aljazeera Private University, Ghabagheb, Syria
| | - Shalinee Jha
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Dominic Goj
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Peter Macheroux
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Silvia Wallner
- Institute of Biochemistry, Graz University of Technology, NAWI Graz, Graz, Austria.
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10
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Westphal AH, Tischler D, van Berkel WJH. Natural diversity of FAD-dependent 4-hydroxybenzoate hydroxylases. Arch Biochem Biophys 2021; 702:108820. [PMID: 33684360 DOI: 10.1016/j.abb.2021.108820] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 01/05/2023]
Abstract
4-Hydroxybenzoate 3-hydroxylase (PHBH) is the most extensively studied group A flavoprotein monooxygenase (FPMO). PHBH is almost exclusively found in prokaryotes, where its induction, usually as a consequence of lignin degradation, results in the regioselective formation of protocatechuate, one of the central intermediates in the global carbon cycle. In this contribution we introduce several less known FAD-dependent 4-hydroxybenzoate hydroxylases. Phylogenetic analysis showed that the enzymes discussed here reside in distinct clades of the group A FPMO family, indicating their separate divergence from a common ancestor. Protein homology modelling revealed that the fungal 4-hydroxybenzoate 3-hydroxylase PhhA is structurally related to phenol hydroxylase (PHHY) and 3-hydroxybenzoate 4-hydroxylase (3HB4H). 4-Hydroxybenzoate 1-hydroxylase (4HB1H) from yeast catalyzes an oxidative decarboxylation reaction and is structurally similar to 3-hydroxybenzoate 6-hydroxylase (3HB6H), salicylate hydroxylase (SALH) and 6-hydroxynicotinate 3-monooxygenase (6HNMO). Genome mining suggests that the 4HB1H activity is widespread in the fungal kingdom and might be responsible for the oxidative decarboxylation of vanillate, an import intermediate in lignin degradation. 4-Hydroxybenzoyl-CoA 1-hydroxylase (PhgA) catalyzes an intramolecular migration reaction (NIH shift) during the three-step conversion of 4-hydroxybenzoate to gentisate in certain Bacillus species. PhgA is phylogenetically related to 4-hydroxyphenylacetate 1-hydroxylase (4HPA1H). In summary, this paper shines light on the natural diversity of group A FPMOs that are involved in the aerobic microbial catabolism of 4-hydroxybenzoate.
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Affiliation(s)
- Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University & Research, Wageningen, the Netherlands.
| | - Dirk Tischler
- Microbial Biotechnology, Faculty of Biology and Biotechnology, Ruhr-Universität Bochum, Germany.
| | - Willem J H van Berkel
- Laboratory of Food Chemistry, Wageningen University & Research, Wageningen, the Netherlands.
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Abstract
Many flavin-dependent phenolic hydroxylases (monooxygenases) have been extensively investigated. Their crystal structures and reaction mechanisms are well understood. These enzymes belong to groups A and D of the flavin-dependent monooxygenases and can be classified as single-component and two-component flavin-dependent monooxygenases. The insertion of molecular oxygen into the substrates catalyzed by these enzymes is beneficial for modifying the biological properties of phenolic compounds and their derivatives. This chapter provides an in-depth discussion of the structural features of single-component and two-component flavin-dependent phenolic hydroxylases. The reaction mechanisms of selected enzymes, including 3-hydroxy-benzoate 4-hydroxylase (PHBH) and 3-hydroxy-benzoate 6-hydroxylase as representatives of single-component enzymes and 3-hydroxyphenylacetate 4-hydroxylase (HPAH) as a representative of two-component enzymes, are discussed in detail. This chapter comprises the following four main parts: general reaction, structures, reaction mechanisms, and enzyme engineering for biocatalytic applications. Enzymes belonging to the same group catalyze similar reactions but have different unique structural features to control their reactivity to substrates and the formation and stabilization of C4a-hydroperoxyflavin. Protein engineering has been employed to improve the ability to use these enzymes to synthesize valuable compounds. A thorough understanding of the structural and mechanistic features controlling enzyme reactivity is useful for enzyme redesign and enzyme engineering for future biocatalytic applications.
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Affiliation(s)
- Pirom Chenprakhon
- Institute for Innovative Learning, Mahidol University, Nakhon Pathom, Thailand.
| | - Panu Pimviriyakul
- Department of Biochemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok, Thailand; Department of Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand
| | - Chanakan Tongsook
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakhon Pathom, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong, Thailand
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12
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Zhu G, Hou C, Yuan W, Wang Z, Zhang J, Jiang L, Karthik L, Li B, Ren B, Lv K, Lu W, Cong Z, Dai H, Hsiang T, Zhang L, Liu X. Molecular networking assisted discovery and biosynthesis elucidation of the antimicrobial spiroketals epicospirocins. Chem Commun (Camb) 2020; 56:10171-10174. [PMID: 32748904 DOI: 10.1039/d0cc03990j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Two pairs of dibenzospiroketal racemates, (±)-epicospirocin A (1a/1b) and (±)-1-epi-epicospirocin A (2a/2b), and two (+)-enantiomers of aspermicrones, ent-aspermicrone B (3b) and ent-aspermicrone C (4b), together with two hemiacetal epimeric mixtures, epicospirocin B/1-epi-epicospirocin B (5/6) and epicospirocin C/1-epi-epicospirocin C (7/8), were investigated from the phytopathogenic fungus Epicoccum nigrum 09116 via MS/MS molecular networking guided isolation and chiral separation for the first time. A plausible epicospirocin biosynthetic pathway was elucidated through in silico gene function annotation together with knock-out experiments. This is the first report that has applied MS/MS molecular networking to identify intermediates correlated with a biosynthetic pathway.
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Affiliation(s)
- Guoliang Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
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13
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Beaupre BA, Reabe KR, Roman JV, Moran GR. Hydrogen movements in the oxidative half-reaction of kynurenine 3-monooxygenase from Pseudomonas fluorescens reveal the mechanism of hydroxylation. Arch Biochem Biophys 2020; 690:108474. [PMID: 32687799 DOI: 10.1016/j.abb.2020.108474] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 06/08/2020] [Accepted: 06/17/2020] [Indexed: 11/30/2022]
Abstract
Kynurenine 3-monoxygenase (KMO) catalyzes the conversion of l-kynurenine (L-Kyn) to 3-hydroxykynurenine (3-OHKyn) in the pathway for tryptophan catabolism. We have investigated the effects of pH and deuterium substitution on the oxidative half-reaction of KMO from P. fluorescens (PfKMO). The three phases observed during the oxidative half reaction are formation of the hydroperoxyflavin, hydroxylation and product release. The measured rate constants for these phases proved largely unchanging with pH, suggesting that the KMO active site is insulated from exchange with solvent during catalysis. A solvent inventory study indicated that a solvent isotope effect of 2-3 is observed for the hydroxylation phase and that two or more protons are in flight during this step. An inverse isotope effect of 0.84 ± 0.01 on the rate constant for the hydroxylation step with ring perdeutero-L-Kyn as a substrate indicates a shift from sp2 to sp3 hybridization in the transition state leading to the formation of a non-aromatic intermediate. The pH dependence of transient state data collected for the substrate analog meta-nitrobenzoylalanine indicate that groups proximal to the hydroperoxyflavin are titrated in the range pH 5-8.5 and can be described by a pKa of 8.8. That higher pH values do not slow the rate of hydroxylation precludes that the pKa measured pertains to the proton of the hydroperoxflavin. Together, these observations indicate that the C4a-hydroperoxyflavin has a pKa ≫ 8.5, that a non-aromatic species is the immediate product of hydroxylation and that at least two solvent derived protons are in-flight during oxygen insertion to the substrate aromatic ring. A unifying mechanistic proposal for these observations is proposed.
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Affiliation(s)
- Brett A Beaupre
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA
| | - Karen R Reabe
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 N. Cramer Street, Milwaukee, WI, 53211-3029, USA
| | - Joseph V Roman
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA
| | - Graham R Moran
- Department of Chemistry and Biochemistry, 1068 W Sheridan Rd, Loyola University Chicago, Chicago, IL, 60660, USA.
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14
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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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15
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Fürst MJLJ, Fiorentini F, Fraaije MW. Beyond active site residues: overall structural dynamics control catalysis in flavin-containing and heme-containing monooxygenases. Curr Opin Struct Biol 2019; 59:29-37. [DOI: 10.1016/j.sbi.2019.01.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 01/25/2019] [Indexed: 12/31/2022]
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16
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Catalytic mechanism for the conversion of salicylate into catechol by the flavin-dependent monooxygenase salicylate hydroxylase. Int J Biol Macromol 2019; 129:588-600. [DOI: 10.1016/j.ijbiomac.2019.01.135] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/24/2019] [Accepted: 01/24/2019] [Indexed: 11/17/2022]
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17
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Singh NS, Sharma R, Singh DK. Identification of enzyme(s) capable of degrading endosulfan and endosulfan sulfate using in silico techniques. Enzyme Microb Technol 2019; 124:32-40. [DOI: 10.1016/j.enzmictec.2019.01.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 11/10/2018] [Accepted: 01/04/2019] [Indexed: 11/28/2022]
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18
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Tolmie C, Smit MS, Opperman DJ. Native roles of Baeyer–Villiger monooxygenases in the microbial metabolism of natural compounds. Nat Prod Rep 2019; 36:326-353. [DOI: 10.1039/c8np00054a] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Baeyer–Villiger monooxygenases function in the primary metabolism of atypical carbon sources, as well as the synthesis of complex microbial metabolites.
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Affiliation(s)
- Carmien Tolmie
- Department of Biotechnology
- University of the Free State
- Bloemfontein
- South Africa
| | - Martha S. Smit
- Department of Biotechnology
- University of the Free State
- Bloemfontein
- South Africa
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19
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Westphal AH, Tischler D, Heinke F, Hofmann S, Gröning JAD, Labudde D, van Berkel WJH. Pyridine Nucleotide Coenzyme Specificity of p-Hydroxybenzoate Hydroxylase and Related Flavoprotein Monooxygenases. Front Microbiol 2018; 9:3050. [PMID: 30631308 PMCID: PMC6315137 DOI: 10.3389/fmicb.2018.03050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 11/27/2018] [Indexed: 12/03/2022] Open
Abstract
p-Hydroxybenzoate hydroxylase (PHBH; EC 1.14.13.2) is a microbial group A flavoprotein monooxygenase that catalyzes the ortho-hydroxylation of 4-hydroxybenzoate to 3,4-dihydroxybenzoate with the stoichiometric consumption of NAD(P)H and oxygen. PHBH and related enzymes lack a canonical NAD(P)H-binding domain and the way they interact with the pyridine nucleotide coenzyme has remained a conundrum. Previously, we identified a surface exposed protein segment of PHBH from Pseudomonas fluorescens involved in NADPH binding. Here, we report the first amino acid sequences of NADH-preferring PHBHs and a phylogenetic analysis of putative PHBHs identified in currently available bacterial genomes. It was found that PHBHs group into three clades consisting of NADPH-specific, NAD(P)H-dependent and NADH-preferring enzymes. The latter proteins frequently occur in Actinobacteria. To validate the results, we produced several putative PHBHs in Escherichia coli and confirmed their predicted coenzyme preferences. Based on phylogeny, protein energy profiling and lifestyle of PHBH harboring bacteria we propose that the pyridine nucleotide coenzyme specificity of PHBH emerged through adaptive evolution and that the NADH-preferring enzymes are the older versions of PHBH. Structural comparison and distance tree analysis of group A flavoprotein monooxygenases indicated that a similar protein segment as being responsible for the pyridine nucleotide coenzyme specificity of PHBH is involved in determining the pyridine nucleotide coenzyme specificity of the other group A members.
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Affiliation(s)
- Adrie H Westphal
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
| | - Dirk Tischler
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Florian Heinke
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Sarah Hofmann
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Janosch A D Gröning
- Interdisziplinäres Ökologisches Zentrum, Technische Universität Bergakademie Freiberg, Freiberg, Germany
| | - Dirk Labudde
- Bioinformatics Group Mittweida, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Willem J H van Berkel
- Laboratory of Biochemistry, Wageningen University and Research, Wageningen, Netherlands
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20
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Chen Q, Huang Y, Duan Y, Li Z, Cui Z, Liu W. Crystal structure of p-nitrophenol 4-monooxygenase PnpA from Pseudomonas putida DLL-E4: The key enzyme involved in p-nitrophenol degradation. Biochem Biophys Res Commun 2018; 504:715-720. [PMID: 30217456 DOI: 10.1016/j.bbrc.2018.09.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/07/2018] [Indexed: 02/07/2023]
Abstract
p-Nitrophenol 4-monooxygenase PnpA, the key enzyme in the hydroquinone pathway of p-nitrophenol (PNP) degradation, catalyzes the monooxygenase reaction of PNP to p-benzoquinone in the presence of FAD and NADH. Here, we determined the first crystal structure of PnpA from Pseudomonas putida DLL-E4 in its apo and FAD-complex forms to a resolution of 2.04 Å and 2.48 Å, respectively. The PnpA structure shares a common fold with hydroxybenzoate hydroxylases, despite a low amino sequence identity of 14-18%, confirming it to be a member of the Class A flavoprotein monooxygenases. However, substrate docking studies of PnpA indicated that the residues stabilizing the substrate in an orientation suitable for catalysis are not observed in other homologous hydroxybenzoate hydroxylases, suggesting PnpA employs a unique catalytic mechanism. This work expands our understanding on the reaction mode for this enzyme class.
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Affiliation(s)
- Qiongzhen Chen
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yan Huang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yajuan Duan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Zhoukun Li
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China.
| | - Weidong Liu
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
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21
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Das B, Patra S. Multisubstrate specific flavin containing monooxygenase from Chlorella pyrenoidosa with potential application for phenolic wastewater remediation and biosensor application. ENVIRONMENTAL TECHNOLOGY 2018; 39:2073-2089. [PMID: 28662620 DOI: 10.1080/09593330.2017.1349838] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Microbial degradation of phenolic pollutants in industrial wastewater is dependent on enzymatic pathway comprising a cascade of phenol metabolizing enzymes. Phenol hydroxylase is the first enzyme of the pathway catalysing the initial attack on phenol in green algae Chlorella pyrenoidosa. The present work reports cost-effective production of partially purified microalgal phenol hydroylase by single-step purification and characterization of its kinetic properties with the view of application for enzyme-based remediation of phenolic wastewater or in phenolic biosensor. The enzyme with a molecular weight of 25 kDa shows all characteristics of phenol hydroxylases, that is, hydroxylation of phenol to catechol (confirmed by HPLC), substrate-dependent NADPH oxidation, absorption spectrum typical of flavoproteins and peptide mass fingerprint corresponding to flavoprotein hydroxylase. The enzyme utilizes phenol with apparent Michealis constant (Km) of 1.71 µM, maximal velocity (Vmax) of 0.4 µM/min with optimal activity at pH 7 and 35°C. Fe2+chelators (Phenanthroline and sodium arsenate), heavy metals, denaturants and oxidizing agents showed inhibitory effect on phenol hydroxylation activity of the enzyme. The enzyme has broad substrate specificity against isomeric diphenols, isomeric methylphenols, halogen-substituted phenols, amino-substituted phenols, nitrophenols, hydroxybenzaldehyde and hydroxylbenzoic acid. The enzyme shows remarkable storage stability at room temperature and at 4°C. The multisubstrate specificity coupled to remarkable storage stability of the microalgal phenol hydroxylase opens up avenues for its application in remediation of a wide range of phenolics released in industrial wastewater or phenolic biosensor application.
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Affiliation(s)
- Bhaskar Das
- a Centre for the Environment , Indian Institute of Technology Guwahati , Guwahati , India
| | - Sanjukta Patra
- b Department of Biosciences and Bioengineering , Indian Institute of Technology Guwahati , Guwahati , India
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22
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Wang Y, Zhang C, An S, Fang X, Yu D. Engineering substrate promiscuity in 2,4-dichlorophenol hydroxylase by in silico design. RSC Adv 2018; 8:21184-21190. [PMID: 35539933 PMCID: PMC9080915 DOI: 10.1039/c8ra03229g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 06/04/2018] [Indexed: 11/21/2022] Open
Abstract
2,4-Dichlorophenol hydroxylase (2,4-DCP hydroxylase) is a key enzyme in the degradation of 2,4-dichlorophenoxyacetic acid in the hydroxylation step in many bacteria. Our previous study demonstrated that a 2,4-DCP hydroxylase (TfdB-JLU) exhibits broad substrate specificity for chlorophenols (CPs) and their homologues. In this study, TfdB-JLU has been engineered by rational design to further broaden its substrate scope towards CPs. We dissect the architectures of enzymes from oxidoreductase families to discover their underlying structural sources of substrate promiscuity. A homology model of TfdB-JLU has been built and docking experiments of this homology model with its natural substrate 2,4-DCP reveal that the phenyl rings of 2,4-DCP form strong interactions with residues His47, Ile48, Trp222, Pro316, and Phe424. These residues are found to be important for substrate binding in the active site. Then, the site-directed mutagenesis strategy has been applied for redesigning substrate promiscuity in TfdB-JLU. The TfdB-JLU-P316Q variant obtained shows a significant enhancement of activity (up to 3.4-fold) toward 10 CP congeners compared to wild-type TfdB-JLU. Interestingly, the active improvements of TfdB-JLU-P316Q toward CP congeners show significant difference, especially for active improvements of positional congeners such as 3-CP (1.1-fold) compared to 4-CP (3.0-fold), as well as 2,3-DCP (1.2-fold) compared to 2,5-DCP (3.4-fold). Structural analysis results indicate that the improvement in substrate promiscuity of the variant enzyme compared to the wild-type enzyme is possibly due to the increase of non-bonding interaction. The results suggest that exploiting enzyme-substrate promiscuity is promising, which would provide a starting point for designing and engineering novel biological catalysts for pollution removal.
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Affiliation(s)
- Ye Wang
- College of Life Science, Jilin University 2699 Qianjin Street Changchun 130012 P. R. China
| | - Chengkai Zhang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, College of Life Science, Jilin University 2699 Qianjin Street Changchun 130012 P. R. China +86-431-85155240 +86-431-85155249
| | - Song An
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, College of Life Science, Jilin University 2699 Qianjin Street Changchun 130012 P. R. China +86-431-85155240 +86-431-85155249
| | - Xuexun Fang
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, College of Life Science, Jilin University 2699 Qianjin Street Changchun 130012 P. R. China +86-431-85155240 +86-431-85155249
| | - Dahai Yu
- Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, College of Life Science, Jilin University 2699 Qianjin Street Changchun 130012 P. R. China +86-431-85155240 +86-431-85155249
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23
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Zheng Q, Gong Y, Guo Y, Zhao Z, Wu Z, Zhou Z, Chen D, Pan L, Liu W. Structural Insights into a Flavin-Dependent [4 + 2] Cyclase that Catalyzes trans-Decalin Formation in Pyrroindomycin Biosynthesis. Cell Chem Biol 2018; 25:718-727.e3. [DOI: 10.1016/j.chembiol.2018.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/28/2018] [Accepted: 03/12/2018] [Indexed: 12/13/2022]
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24
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Romero E, Gómez Castellanos JR, Gadda G, Fraaije MW, Mattevi A. Same Substrate, Many Reactions: Oxygen Activation in Flavoenzymes. Chem Rev 2018; 118:1742-1769. [DOI: 10.1021/acs.chemrev.7b00650] [Citation(s) in RCA: 216] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Elvira Romero
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - J. Rubén Gómez Castellanos
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Giovanni Gadda
- Departments of Chemistry and Biology, Center for Diagnostics and Therapeutics, and Center for Biotechnology and Drug Design, Georgia State University, Atlanta, Georgia 30302-3965, United States
| | - Marco W. Fraaije
- Molecular Enzymology Group, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Andrea Mattevi
- Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
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25
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Zhang C, Fu L, Xu Z, Xiong H, Zhou D, Huo M. Contrasting roles of phenol and pyrocatechol on the degradation of 4-chlorophenol in a photocatalytic–biological reactor. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:24725-24731. [PMID: 28942472 DOI: 10.1007/s11356-017-0245-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 09/19/2017] [Indexed: 05/24/2023]
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26
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Keirsse-Haquin J, Picaud T, Bordes L, de Gracia AG, Desbois A. Modulation of the flavin-protein interactions in NADH peroxidase and mercuric ion reductase: a resonance Raman study. EUROPEAN BIOPHYSICS JOURNAL : EBJ 2017; 47:205-223. [PMID: 28889232 DOI: 10.1007/s00249-017-1245-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 07/12/2017] [Accepted: 07/26/2017] [Indexed: 10/18/2022]
Abstract
NADH peroxidase (Npx) and mercuric ion reductase (MerA) are flavoproteins belonging to the pyridine nucleotide:disulfide oxidoreductases (PNDO) and catalyzing the reduction of toxic substrates, i.e., hydrogen peroxide and mercuric ion, respectively. To determine the role of the flavin adenine dinucleotide (FAD) in the detoxification mechanism, the resonance Raman (RR) spectra of these enzymes under various redox and ligation states have been investigated using blue and/or near-UV excitation(s). These data were compared to those previously obtained for glutathione reductase (GR), another enzyme of the PNDO family, but catalyzing the reduction of oxidized glutathione. Spectral differences have been detected for the marker bands of the isoalloxazine ring of Npx, MerA, and GR. They provide evidence for different catalytic mechanisms in these flavoproteins. The RR modes of the oxidized and two-electron reduced (EH2) forms of Npx are related to very tight flavin-protein interactions maintaining a nearly planar conformation of the isoalloxazine tricycle, a low level of H-bonding at the N1/N5 and O2/O4 sites, and a strong H-bond at N3H. They also indicate minimal changes in FAD structure and environment upon either NAD(H) binding or reduction of the sulfinic redox center. All these spectroscopic data support an enzyme functioning centered on the Cys-SO-/Cys-S- redox moiety and a neighbouring His residue. On the contrary, the RR data on various functional forms of MerA are indicative of a modulation of both ring II distortion and H-bonding states of the N5 site and ring III. The Cd(II) binding to the EH2-NADP(H) complexes, biomimetic intermediates in the reaction of Hg(II) reduction, provokes important spectral changes. They are interpreted in terms of flattening of the isoalloxazine ring and large decreases in H-bonding at the N5 site and ring III. The large flexibility of the FAD structure and environment in MerA is in agreement with proposed mechanisms involving C4a(flavin) adducts.
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Affiliation(s)
- Julie Keirsse-Haquin
- Institut de Biologie Intégrative de la Cellule, UMR 9198 CNRS-CEA-Université Paris Sud, CEA Saclay, 91191, Gif-sur-Yvette Cedex, France.,Ecole Nationale Supérieure des Mines, 44300, Nantes, France
| | - Thierry Picaud
- Institut de Biologie Intégrative de la Cellule, UMR 9198 CNRS-CEA-Université Paris Sud, CEA Saclay, 91191, Gif-sur-Yvette Cedex, France.,Institut Supérieur des Biotechnologies de Paris (Sup'Biotech Paris), 94800, Villejuif, France
| | - Luc Bordes
- Institut de Biologie Intégrative de la Cellule, UMR 9198 CNRS-CEA-Université Paris Sud, CEA Saclay, 91191, Gif-sur-Yvette Cedex, France.,School of Earth and Environmental Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Adrienne Gomez de Gracia
- Institut de Biologie Intégrative de la Cellule, UMR 9198 CNRS-CEA-Université Paris Sud, CEA Saclay, 91191, Gif-sur-Yvette Cedex, France
| | - Alain Desbois
- Institut de Biologie Intégrative de la Cellule, UMR 9198 CNRS-CEA-Université Paris Sud, CEA Saclay, 91191, Gif-sur-Yvette Cedex, France.
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27
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Liu LK, Abdelwahab H, Martin Del Campo JS, Mehra-Chaudhary R, Sobrado P, Tanner JJ. The Structure of the Antibiotic Deactivating, N-hydroxylating Rifampicin Monooxygenase. J Biol Chem 2016; 291:21553-21562. [PMID: 27557658 PMCID: PMC5076826 DOI: 10.1074/jbc.m116.745315] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/22/2016] [Indexed: 11/06/2022] Open
Abstract
Rifampicin monooxygenase (RIFMO) catalyzes the N-hydroxylation of the natural product antibiotic rifampicin (RIF) to 2'-N-hydroxy-4-oxo-rifampicin, a metabolite with much lower antimicrobial activity. RIFMO shares moderate sequence similarity with well characterized flavoprotein monooxygenases, but the protein has not been isolated and characterized at the molecular level. Herein, we report crystal structures of RIFMO from Nocardia farcinica, the determination of the oligomeric state in solution with small angle x-ray scattering, and the spectrophotometric characterization of substrate binding. The structure identifies RIFMO as a class A flavoprotein monooxygenase and is similar in fold and quaternary structure to MtmOIV and OxyS, which are enzymes in the mithramycin and oxytetracycline biosynthetic pathways, respectively. RIFMO is distinguished from other class A flavoprotein monooxygenases by its unique middle domain, which is involved in binding RIF. Small angle x-ray scattering analysis shows that RIFMO dimerizes via the FAD-binding domain to form a bell-shaped homodimer in solution with a maximal dimension of 110 Å. RIF binding was monitored using absorbance at 525 nm to determine a dissociation constant of 13 μm Steady-state oxygen consumption assays show that NADPH efficiently reduces the FAD only when RIF is present, implying that RIF binds before NADPH in the catalytic scheme. The 1.8 Å resolution structure of RIFMO complexed with RIF represents the precatalytic conformation that occurs before formation of the ternary E-RIF-NADPH complex. The RIF naphthoquinone blocks access to the FAD N5 atom, implying that large conformational changes are required for NADPH to reduce the FAD. A model for these conformational changes is proposed.
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Affiliation(s)
- Li-Kai Liu
- From the Departments of Biochemistry and
| | - Heba Abdelwahab
- the Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, and
- the Department of Chemistry, Faculty of Science, Damietta University, Damietta 34517, Egypt
| | | | | | - Pablo Sobrado
- the Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, and
| | - John J Tanner
- From the Departments of Biochemistry and
- Chemistry and
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28
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Zhou W, Guo W, Zhou H, Chen X. Phenol degradation by Sulfobacillus acidophilus TPY via the meta -pathway. Microbiol Res 2016; 190:37-45. [DOI: 10.1016/j.micres.2016.05.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 05/11/2016] [Accepted: 05/13/2016] [Indexed: 11/30/2022]
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29
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Xiao X, Si M, Yang Z, Zhang Y, Guan J, Chaudhry MT, Wang Y, Shen X. Molecular characterization of a eukaryotic-like phenol hydroxylase from Corynebacterium glutamicum. J GEN APPL MICROBIOL 2016; 61:99-107. [PMID: 26377129 DOI: 10.2323/jgam.61.99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
This study focuses on the genetic and biochemical characterization of phenol hydroxylase (Phe, NCgl2588) from Corynebacterium glutamicum that shares 31% identity in amino acids with phenol hydroxylase from yeast Trichosporon cutaneum but less similarity with that from bacteria. The phe deletion mutant significantly reduced its ability to grow with phenol as the sole carbon and energy source. Expression of the phe gene was strongly induced with phenol and also subject to the control of carbon catabolite repression (CCR). The molecular weight of purified Phe protein determined by gel filtration chromatography was 70 kDa, indicating that Phe exists as a monomer in the purification condition. However, Phe protein pre-incubated with phenol showed a molecular weight of 140 kDa, suggesting that Phe is likely active as a dimer. In addition to phenol, the Phe protein could utilize various other phenolic compounds as substrates. Site-directed mutagenesis revealed that D75, P261, R262, R269, C349 and C476 are key amino acid residues closely related to the enzyme activity of Phe.
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Affiliation(s)
- Xiao Xiao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University
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Lobo CC, Bertola NC, Contreras EM. INHIBITION KINETICS DURING THE OXIDATION OF BINARY MIXTURES OF PHENOL WITH CATECHOL, RESORCINOL AND HYDROQUINONE BY PHENOL ACCLIMATED ACTIVATED SLUDGE. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2016. [DOI: 10.1590/0104-6632.20160331s20150173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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31
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Sucharitakul J, Medhanavyn D, Pakotiprapha D, van Berkel WJH, Chaiyen P. Tyr217 and His213 are important for substrate binding and hydroxylation of 3-hydroxybenzoate 6-hydroxylase fromRhodococcus jostiiRHA1. FEBS J 2016; 283:860-81. [DOI: 10.1111/febs.13636] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/03/2015] [Accepted: 12/21/2015] [Indexed: 01/28/2023]
Affiliation(s)
- Jeerus Sucharitakul
- Department of Biochemistry; Faculty of Dentistry; Chulalongkorn University; Bangkok Thailand
| | - Dheeradhach Medhanavyn
- Department of Biochemistry and Center for Excellence in Proteins and Enzyme Technology; Faculty of Science; Mahidol University; Bangkok Thailand
| | - Danaya Pakotiprapha
- Department of Biochemistry and Center for Excellence in Proteins and Enzyme Technology; Faculty of Science; Mahidol University; Bangkok Thailand
| | | | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Proteins and Enzyme Technology; Faculty of Science; Mahidol University; Bangkok Thailand
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Kanteev M, Bregman-Cohen A, Deri B, Shahar A, Adir N, Fishman A. A crystal structure of 2-hydroxybiphenyl 3-monooxygenase with bound substrate provides insights into the enzymatic mechanism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1906-1913. [PMID: 26275805 DOI: 10.1016/j.bbapap.2015.08.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 08/06/2015] [Accepted: 08/09/2015] [Indexed: 11/16/2022]
Abstract
2-Hydroxybiphenyl 3-monooxygenase (HbpA) is an FAD dependent monooxygenase which catalyzes the ortho-hydroxylation of a broad range of 2-substituted phenols in the presence of NADH and molecular oxygen. We have determined the structure of HbpA from the soil bacterium Pseudomonas azelaica HBP1 with bound 2-hydroxybiphenyl, as well as several variants, at a resolution of 2.3-2.5Å to investigate structure function correlations of the enzyme. An observed hydrogen bond between 2-hydroxybiphenyl and His48 in the active site confirmed the previously suggested role of this residue in substrate deprotonation. The entrance to the active site was confirmed by generating variant G255F which exhibited only 7% of the wild-type's specific activity of product formation, suggesting inhibition of substrate entrance into the active site by the large aromatic residue. Residue Arg242 is suggested to facilitate FAD movement and reduction as was previously reported in studies on the homologous protein para-hydroxybenzoate hydroxylase. In addition, it is suggested that Trp225, which is located in the active site, facilitates proper substrate entrance into the binding pocket in contrast to aklavinone-11-hydroxylase and para-hydroxybenzoate hydroxylase in which a residue at a similar position is responsible for substrate deprotonation. Structure function correlations described in this work will aid in the design of variants with improved activity and altered selectivity for potential industrial applications.
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Affiliation(s)
- Margarita Kanteev
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Almog Bregman-Cohen
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Batel Deri
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Anat Shahar
- Macromolecular Crystallography Research Center (MCRC), Department of Life Sciences & NIBN, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ayelet Fishman
- Department of Biotechnology and Food Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
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Jensen CN, Mielke T, Farrugia JE, Frank A, Man H, Hart S, Turkenburg JP, Grogan G. Structures of the Apo and FAD-bound forms of 2-hydroxybiphenyl 3-monooxygenase (HbpA) locate activity hotspots identified by using directed evolution. Chembiochem 2015; 16:968-76. [PMID: 25737306 PMCID: PMC4515095 DOI: 10.1002/cbic.201402701] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Indexed: 11/09/2022]
Abstract
The FAD-dependent monooxygenase HbpA from Pseudomonas azelaica HBP1 catalyses the hydroxylation of 2-hydroxybiphenyl (2HBP) to 2,3-dihydroxybiphenyl (23DHBP). HbpA has been used extensively as a model for studying flavoprotein hydroxylases under process conditions, and has also been subjected to directed-evolution experiments that altered its catalytic properties. The structure of HbpA has been determined in its apo and FAD-complex forms to resolutions of 2.76 and 2.03 Å, respectively. Comparisons of the HbpA structure with those of homologues, in conjunction with a model of the reaction product in the active site, reveal His48 as the most likely acid/base residue to be involved in the hydroxylation mechanism. Mutation of His48 to Ala resulted in an inactive enzyme. The structures of HbpA also provide evidence that mutants achieved by directed evolution that altered activity are comparatively remote from the substrate-binding site.
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Affiliation(s)
- Chantel N Jensen
- York Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York, YO10 5DD (UK)
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Long Y, Yang S, Xie Z, Cheng L. Identification and characterization of phenol hydroxylase from phenol-degrading Candida tropicalis strain JH8. Can J Microbiol 2014; 60:585-91. [DOI: 10.1139/cjm-2014-0417] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The gene phhY encoding phenol hydroxylase from Candida tropicalis JH8 was cloned, sequenced, and expressed in Escherichia coli. The gene phhY contained an open reading frame of 2130 bp encoding a polypeptide of 709 amino acid residues. From its sequence analysis, it is a member of a family of flavin-containing aromatic hydroxylases and shares 41% amino acid identity with phenol hydroxylase from Trichosporon cutaneum. The recombinant phenol hydroxylase exists as a homotetramer structure with a native molecular mass of 320 kDa. Recombinant phenol hydroxylase was insensitive to pH treatment; its optimum pH was at 7.6. The optimum temperature for the enzyme was 30 °C, and its activity was rapidly lost at temperatures above 60 °C. Under the optimal conditions with phenol as substrate, the Km and Vmax of recombinant phenol hydroxylase were 0.21 mmol·L–1 and 0.077 μmol·L–1·min−1, respectively. This is the first paper presenting the cloning and expression in E. coli of the phenol hydroxylase gene from C. tropicalis and the characterization of the recombinant phenol hydroxylase.
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Affiliation(s)
- Yan Long
- College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), State Key Laboratory of Virology, Wuhan University, Wuhan 430072, People’s Republic of China
- Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Wuhan 430072, People’s Republic of China
| | - Sheng Yang
- College of Life Sciences, Hubei University, Wuhan 430062, People’s Republic of China
| | - Zhixiong Xie
- College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), State Key Laboratory of Virology, Wuhan University, Wuhan 430072, People’s Republic of China
- Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Wuhan 430072, People’s Republic of China
| | - Li Cheng
- College of Life Sciences, Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), State Key Laboratory of Virology, Wuhan University, Wuhan 430072, People’s Republic of China
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Granda JM, Staszewska-Krajewska O, Jurczak J. Bispyrrolylbenzene Anion Receptor: From Supramolecular Switch to Molecular Logic Gate. Chemistry 2014; 20:12790-5. [DOI: 10.1002/chem.201403116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Indexed: 11/09/2022]
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Goldman PJ, Ryan KS, Hamill MJ, Howard-Jones AR, Walsh CT, Elliott SJ, Drennan CL. An unusual role for a mobile flavin in StaC-like indolocarbazole biosynthetic enzymes. ACTA ACUST UNITED AC 2014; 19:855-65. [PMID: 22840773 DOI: 10.1016/j.chembiol.2012.05.016] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2012] [Revised: 05/10/2012] [Accepted: 05/15/2012] [Indexed: 11/15/2022]
Abstract
The indolocarbazole biosynthetic enzymes StaC, InkE, RebC, and AtmC mediate the degree of oxidation of chromopyrrolic acid on route to the natural products staurosporine, K252a, rebeccamycin, and AT2433-A1, respectively. Here, we show that StaC and InkE, which mediate a net 4-electron oxidation, bind FAD with a micromolar K(d), whereas RebC and AtmC, which mediate a net 8-electron oxidation, bind FAD with a nanomolar K(d) while displaying the same FAD redox properties. We further create RebC-10x, a RebC protein with ten StaC-like amino acid substitutions outside of previously characterized FAD-binding motifs and the complementary StaC-10x. We find that these mutations mediate both FAD affinity and product specificity, with RebC-10x displaying higher StaC activity than StaC itself. X-ray structures of this StaC catalyst identify the substrate of StaC as 7-carboxy-K252c and suggest a unique mechanism for this FAD-dependent enzyme.
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Affiliation(s)
- Peter J Goldman
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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Trivedi VD, Majhi P, Phale PS. Kinetic and spectroscopic characterization of 1-naphthol 2-hydroxylase from Pseudomonas sp. strain C5. Appl Biochem Biotechnol 2014; 172:3964-77. [PMID: 24599669 DOI: 10.1007/s12010-014-0815-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 02/17/2014] [Indexed: 11/27/2022]
Abstract
1-Naphthol 2-hydroxylase (1-NH) catalyzes the conversion of 1-naphthol to 1,2-dihydroxynaphthalene. 1-NH from carbaryl degrading Pseudomonas strain C5 was purified and characterized for its kinetic and spectroscopic properties. The enzyme was found to be NAD(P)H-dependent external flavin monooxygenase. Though the kinetic parameters of 1-NH from strain C5 appear to be similar to 1-NH enzyme from strains C4 and C6, however, they differ in their N-terminal sequences, mole content of flavin adenine dinucleotide (FAD), reconstitution of apoenzyme, and K i. 1-NH showed narrow substrate specificity with comparable hydroxylation efficiency on 1-naphthol and 5-amino 1-naphthol (~30 %) followed by 4-chloro 1-naphthol (~9 %). Salicylate was found to be the nonsubstrate effector. The flavin fluorescence of 1-NH was found to increase in the presence of 1-naphthol (K d = 11.3 μM) and salicylate (K d = 1027 μM). The circular dichroism (CD) spectra showed significant perturbations in the presence of NAD(P)H, whereas no changes were observed in the presence of 1-naphthol. Naphthalene, 1-chloronaphthalene, 2-napthol, and 2-naphthoic acid were found to be the mixed inhibitors. Chemical modification studies showed the probable involvement of His, Cys, and Tyr in the binding of 1-naphthol, whereas Trp was found to be involved in the binding of NAD(P)H.
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Affiliation(s)
- Vikas D Trivedi
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai, 400 076, India
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38
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El-Sayed WS, Ibrahim MK, Ouf SA. Molecular characterization of the alpha subunit of multicomponent phenol hydroxylase from 4-chlorophenol-degrading Pseudomonas sp. strain PT3. J Microbiol 2014; 52:13-9. [DOI: 10.1007/s12275-014-3250-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 08/06/2013] [Accepted: 08/13/2013] [Indexed: 11/30/2022]
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Montersino S, Orru R, Barendregt A, Westphal AH, van Duijn E, Mattevi A, van Berkel WJH. Crystal structure of 3-hydroxybenzoate 6-hydroxylase uncovers lipid-assisted flavoprotein strategy for regioselective aromatic hydroxylation. J Biol Chem 2013; 288:26235-26245. [PMID: 23864660 DOI: 10.1074/jbc.m113.479303] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
3-Hydroxybenzoate 6-hydroxylase (3HB6H) from Rhodococcus jostii RHA1 is a dimeric flavoprotein that catalyzes the NADH- and oxygen-dependent para-hydroxylation of 3-hydroxybenzoate to 2,5-dihydroxybenzoate. In this study, we report the crystal structure of 3HB6H as expressed in Escherichia coli. The overall fold of 3HB6H is similar to that of p-hydroxybenzoate hydroxylase and other flavoprotein aromatic hydroxylases. Unexpectedly, a lipid ligand is bound to each 3HB6H monomer. Mass spectral analysis identified the ligand as a mixture of phosphatidylglycerol and phosphatidylethanolamine. The fatty acid chains occupy hydrophobic channels that deeply penetrate into the interior of the substrate-binding domain of each subunit, whereas the hydrophilic part is exposed on the protein surface, connecting the dimerization domains via a few interactions. Most remarkably, the terminal part of a phospholipid acyl chain is directly involved in the substrate-binding site. Co-crystallized chloride ion and the crystal structure of the H213S variant with bound 3-hydroxybenzoate provide hints about oxygen activation and substrate hydroxylation. Essential roles are played by His-213 in catalysis and Tyr-105 in substrate binding. This phospholipid-assisted strategy to control regioselective aromatic hydroxylation is of relevance for optimization of flavin-dependent biocatalysts.
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Affiliation(s)
- Stefania Montersino
- From the Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | - Roberto Orru
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy, and
| | - Arjan Barendregt
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Adrie H Westphal
- From the Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands
| | - Esther van Duijn
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research, and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - Andrea Mattevi
- Department of Biology and Biotechnology, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy, and.
| | - Willem J H van Berkel
- From the Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands,.
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40
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Hydroquinone: environmental pollution, toxicity, and microbial answers. BIOMED RESEARCH INTERNATIONAL 2013; 2013:542168. [PMID: 23936816 PMCID: PMC3727088 DOI: 10.1155/2013/542168] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 06/20/2013] [Indexed: 12/12/2022]
Abstract
Hydroquinone is a major benzene metabolite, which is a well-known haematotoxic and carcinogenic agent associated with malignancy in occupational environments. Human exposure to hydroquinone can occur by dietary, occupational, and environmental sources. In the environment, hydroquinone showed increased toxicity for aquatic organisms, being less harmful for bacteria and fungi. Recent pieces of evidence showed that hydroquinone is able to enhance carcinogenic risk by generating DNA damage and also to compromise the general immune responses which may contribute to the impaired triggering of the host immune reaction. Hydroquinone bioremediation from natural and contaminated sources can be achieved by the use of a diverse group of microorganisms, ranging from bacteria to fungi, which harbor very complex enzymatic systems able to metabolize hydroquinone either under aerobic or anaerobic conditions. Due to the recent research development on hydroquinone, this review underscores not only the mechanisms of hydroquinone biotransformation and the role of microorganisms and their enzymes in this process, but also its toxicity.
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41
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Kallio P, Patrikainen P, Belogurov GA, Mäntsälä P, Yang K, Niemi J, Metsä-Ketelä M. Tracing the evolution of angucyclinone monooxygenases: structural determinants for C-12b hydroxylation and substrate inhibition in PgaE. Biochemistry 2013; 52:4507-16. [PMID: 23731237 DOI: 10.1021/bi400381s] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Two functionally distinct homologous flavoprotein hydroxylases, PgaE and JadH, have been identified as branching points in the biosynthesis of the polyketide antibiotics gaudimycin C and jadomycin A, respectively. These evolutionarily related enzymes are both bifunctional and able to catalyze the same initial reaction, C-12 hydroxylation of the common angucyclinone intermediate prejadomycin. The enzymes diverge in their secondary activities, which include hydroxylation at C-12b by PgaE and dehydration at C-4a/C-12b by JadH. A further difference is that the C-12 hydroxylation is subject to substrate inhibition only in PgaE. Here we have identified regions associated with the C-12b hydroxylation in PgaE by extensive chimeragenesis, focusing on regions surrounding the active site. The results highlight the importance of a hairpin-β motif near the dimer interface, with two nonconserved residues, P78 and I79 (corresponding to Q89 and F90, respectively, in JadH), and invariant residue H73 playing key roles. Kinetic characterization of PgaE variants demonstrates that the secondary C-12b hydroxylation and substrate inhibition by prejadomycin are likely to be interlinked. The crystal structure of the PgaE P78Q/I79F variant at 2.4 Å resolution confirms that the changes do not alter the conformation of the β-strand secondary structure and that the side chains of these residues in effect point away from the active site toward the dimer interface. The results support a catalytic model for PgaE containing two binding modes for C-12 and C-12b hydroxylations, where binding of prejadomycin in the orientation for C-12b hydroxylation leads to substrate inhibition. The presence of an allosteric network is evident based on enzyme kinetics.
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Affiliation(s)
- Pauli Kallio
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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42
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Lobo CC, Bertola NC, Contreras EM. Stoichiometry and kinetic of the aerobic oxidation of phenolic compounds by activated sludge. BIORESOURCE TECHNOLOGY 2013; 136:58-65. [PMID: 23562772 DOI: 10.1016/j.biortech.2013.02.079] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 01/23/2013] [Accepted: 02/22/2013] [Indexed: 06/02/2023]
Abstract
The aerobic degradation of phenol (PH), catechol (CA), resorcinol (RE), pyrogallol (PY), and hydroquinone (HY) by phenol-acclimated activated sludge was investigated. A Haldane-type dependence of the respiration rate on PH, RE, and HY was observed; CA and PY exhibited a biphasic respiration pattern. According to the initial biodegradation rate, tested compounds were ordered as follows: CA>PH>>PYRE>HY. Also, they exhibited the following degree of toxicity to their own degradation: PY>>CARE>>PH>HY. Oxidation coefficients for PH, PY, RE, and HY were constant as a function of the consecutive additions of the compound. Conversely, an increase of YO/S from 1 to 1.5 molO2 molCA(-1) was observed during repeated additions of CA. The role of some enzymes involved in the aerobic degradation pathways of the tested compounds is discussed and related to the obtained results.
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Affiliation(s)
- Cintia C Lobo
- Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), CONICET, Fac. de Cs. Exactas, UNLP. 47 y 116 B1900AJJ, La Plata, Argentina.
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Hicks KA, O’Leary SE, Begley TP, Ealick SE. Structural and mechanistic studies of HpxO, a novel flavin adenine dinucleotide-dependent urate oxidase from Klebsiella pneumoniae. Biochemistry 2013; 52:477-87. [PMID: 23259842 PMCID: PMC3552057 DOI: 10.1021/bi301262p] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
HpxO is a flavin-dependent urate oxidase that catalyzes the hydroxylation of uric acid to 5-hydroxyisourate and functions in a novel pathway for purine catabolism found in Klebsiella pneumoniae. We have determined the structures of HpxO with and without uric acid at 2.0 and 2.2 Å, respectively. We have also determined the structure of the R204Q variant at 2.0 Å resolution in the absence of uric acid. The variant structure is very similar to that of wild-type HpxO except for the conformation of Arg103, which interacts with FAD in the variant but not in the wild-type structure. Interestingly, the R204Q variant results in the uncoupling of nicotinamide adenine dinucleotide oxidation from uric acid hydroxylation. This suggests that Arg204 facilitates the deprotonation of uric acid, activating it for the oxygen transfer. On the basis of these data, a mechanism for this reaction consisting of a nucleophilic attack of the urate anion on the flavin hydroperoxide resulting in the formation of 5-hydroxyisourate is proposed.
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Affiliation(s)
- Katherine A. Hicks
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
| | - Seán E. O’Leary
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
- Department of Chemistry, Texas A&M University, College Station, Texas 77842
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77842
| | - Steven E. Ealick
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853
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44
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Krastanov A, Alexieva Z, Yemendzhiev H. Microbial degradation of phenol and phenolic derivatives. Eng Life Sci 2013. [DOI: 10.1002/elsc.201100227] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Albert Krastanov
- Department of Biotechnology; University of Food Technologies; Plovdiv; Bulgaria
| | - Zlatka Alexieva
- Institute of Microbiology; Bulgarian Academy of Sciences; Sofia; Bulgaria
| | - Husein Yemendzhiev
- Department of Water Technology; University “Prof. Asen Zlatarov”; Burgas; Bulgaria
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Form follows function: structural and catalytic variation in the class a flavoprotein monooxygenases. Int J Mol Sci 2012; 13:15601-39. [PMID: 23443084 PMCID: PMC3546652 DOI: 10.3390/ijms131215601] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/08/2012] [Accepted: 11/09/2012] [Indexed: 12/02/2022] Open
Abstract
Flavoprotein monooxygenases (FPMOs) exhibit an array of mechanistic solutions to a common chemical objective; the monooxygenation of a target substrate. Each FPMO efficiently couples reduction of a flavin cofactor by NAD(P)H to oxygenation of the target substrate via a (hydro)peroxyflavin intermediate. This purpose of this review is to describe in detail the Class A flavoprotein hydroxylases (FPMO) in the context of the other FPMO classes (B–F). Both one and two component FPMOs are found in nature. Two-component enzymes require, in addition to the monooxygenase, the involvement of a reductase that first catalyzes the reduction of the flavin by NAD(P)H. The Class A and B FPMOs are single-component and manage to orchestrate the same net reaction within a single peptide. The Class A enzymes have, by some considerable margin, the most complete research record. These enzymes use choreographed movements of the flavin ring that facilitate access of the organic substrates to the active site, provide a means for interaction of NADPH with the flavin, offer a mechanism to sequester the dioxygen reduction chemistry from solvent and a means to release the product. The majority of the discrete catalytic events of the catalytic cycle can be observed directly in exquisite detail using spectrophotometric kinetic methods and many of the key mechanistic conclusions are further supported by structural data. This review attempts to compile each of the key observations made for both paradigm and newly discovered examples of Class A FPMOs into a complete catalytic description of one enzymatic turnover.
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46
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Khazanov NA, Damm-Ganamet KL, Quang DX, Carlson HA. Overcoming sequence misalignments with weighted structural superposition. Proteins 2012; 80:2523-35. [PMID: 22733542 DOI: 10.1002/prot.24134] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 06/05/2012] [Accepted: 06/10/2012] [Indexed: 11/09/2022]
Abstract
An appropriate structural superposition identifies similarities and differences between homologous proteins that are not evident from sequence alignments alone. We have coupled our Gaussian-weighted RMSD (wRMSD) tool with a sequence aligner and seed extension (SE) algorithm to create a robust technique for overlaying structures and aligning sequences of homologous proteins (HwRMSD). HwRMSD overcomes errors in the initial sequence alignment that would normally propagate into a standard RMSD overlay. SE can generate a corrected sequence alignment from the improved structural superposition obtained by wRMSD. HwRMSD's robust performance and its superiority over standard RMSD are demonstrated over a range of homologous proteins. Its better overlay results in corrected sequence alignments with good agreement to HOMSTRAD. Finally, HwRMSD is compared to established structural alignment methods: FATCAT, secondary-structure matching, combinatorial extension, and Dalilite. Most methods are comparable at placing residue pairs within 2 Å, but HwRMSD places many more residue pairs within 1 Å, providing a clear advantage. Such high accuracy is essential in drug design, where small distances can have a large impact on computational predictions. This level of accuracy is also needed to correct sequence alignments in an automated fashion, especially for omics-scale analysis. HwRMSD can align homologs with low-sequence identity and large conformational differences, cases where both sequence-based and structural-based methods may fail. The HwRMSD pipeline overcomes the dependency of structural overlays on initial sequence pairing and removes the need to determine the best sequence-alignment method, substitution matrix, and gap parameters for each unique pair of homologs.
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Affiliation(s)
- Nickolay A Khazanov
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109-2218, USA
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Hlouchova K, Rudolph J, Pietari JMH, Behlen LS, Copley SD. Pentachlorophenol hydroxylase, a poorly functioning enzyme required for degradation of pentachlorophenol by Sphingobium chlorophenolicum. Biochemistry 2012; 51:3848-60. [PMID: 22482720 DOI: 10.1021/bi300261p] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several strains of Sphingobium chlorophenolicum have been isolated from soil that was heavily contaminated with pentachlorophenol (PCP), a toxic pesticide introduced in the 1930s. S. chlorophenolicum appears to have assembled a poorly functioning pathway for degradation of PCP by patching enzymes recruited via two independent horizontal gene transfer events into an existing metabolic pathway. Flux through the pathway is limited by PCP hydroxylase. PCP hydroxylase is a dimeric protein that belongs to the family of flavin-dependent phenol hydroxylases. In the presence of NADPH, PCP hydroxylase converts PCP to tetrachlorobenzoquinone (TCBQ). The k(cat) for PCP (0.024 s(-1)) is very low, suggesting that the enzyme is not well evolved for turnover of this substrate. Structure-activity studies reveal that substrate binding and activity are enhanced by a low pK(a) for the phenolic proton, increased hydrophobicity, and the presence of a substituent ortho to the hydroxyl group of the phenol. PCP hydroxylase exhibits substantial uncoupling; the C4a-hydroxyflavin intermediate, instead of hydroxylating the substrate, can decompose to produce H(2)O(2) in a futile cycle that consumes NADPH. The extent of uncoupling varies from 0 to 100% with different substrates. The extent of uncoupling is increased by the presence of bulky substituents at position 3, 4, or 5 and decreased by the presence of a chlorine in the ortho position. The effectiveness of PCP hydroxylase is additionally hindered by its promiscuous activity with tetrachlorohydroquinone (TCHQ), a downstream metabolite in the degradation pathway. The conversion of TCHQ to TCBQ reverses flux through the pathway. Substantial uncoupling also occurs during the reaction with TCHQ.
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Affiliation(s)
- Klara Hlouchova
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado 80309, USA
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Yachnin BJ, Sprules T, McEvoy MB, Lau PCK, Berghuis AM. The substrate-bound crystal structure of a Baeyer-Villiger monooxygenase exhibits a Criegee-like conformation. J Am Chem Soc 2012; 134:7788-95. [PMID: 22506764 PMCID: PMC3349289 DOI: 10.1021/ja211876p] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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The Baeyer–Villiger monooxygenases (BVMOs) are
a family of bacterial flavoproteins that catalyze the synthetically
useful Baeyer–Villiger oxidation reaction. This involves the
conversion of ketones into esters or cyclic ketones into lactones
by introducing an oxygen atom adjacent to the carbonyl group. The
BVMOs offer exquisite regio- and enantiospecificity while acting on
a wide range of substrates. They use only NADPH and oxygen as cosubstrates,
and produce only NADP+ and water as byproducts, making
them environmentally attractive for industrial purposes. Here, we
report the first crystal structure of a BVMO, cyclohexanone monooxygenase
(CHMO) from Rhodococcus sp. HI-31 in complex with
its substrate, cyclohexanone, as well as NADP+ and FAD,
to 2.4 Å resolution. This structure shows a drastic rotation
of the NADP+ cofactor in comparison to previously reported
NADP+-bound structures, as the nicotinamide moiety is no
longer positioned above the flavin ring. Instead, the substrate, cyclohexanone,
is found at this location, in an appropriate position for the formation
of the Criegee intermediate. The rotation of NADP+ permits
the substrate to gain access to the reactive flavin peroxyanion intermediate
while preventing it from diffusing out of the active site. The structure
thus reveals the conformation of the enzyme during the key catalytic
step. CHMO is proposed to undergo a series of conformational changes
to gradually move the substrate from the solvent, via binding in a
solvent excluded pocket that dictates the enzyme’s chemospecificity,
to a location above the flavin–peroxide adduct where catalysis
occurs.
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Affiliation(s)
- Brahm J Yachnin
- Department of Biochemistry, McGill University, 3649 Promenade Sir William Osler, Bellini Pavilion, Room 466, Montreal, QC, Canada H3G 0B1
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Abstract
Abnormally discharged phenols work as toxic pollutants to living environments. In this work, the operation conditions of a newly isolated 2,3-dimethylphenol-degrading Pseudomonas strain including temperature, dissolved oxygen, and pH were investigated. Mixed phenols could be degraded efficiently in diluted mineral-salts medium, avoiding excessive ammonia and phosphate pollution. The results illustrated the potential of bacterial remediation of phenolic pollutants without eutrophication caused by the addition of bacterial growth nutrients.
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Bach RD. Role of the Somersault Rearrangement in the Oxidation Step for Flavin Monooxygenases (FMO). A Comparison between FMO and Conventional Xenobiotic Oxidation with Hydroperoxides. J Phys Chem A 2011; 115:11087-100. [DOI: 10.1021/jp208087u] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert D. Bach
- Department of Chemistry and Biochemistry, University of Delaware, Delaware, United States
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