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Hu P, Chen H, Zhao D, Ma Z, Zeng W, Han Y, Zhou T, Cao J, Shen M. Azomycin Orchestrate Colistin-Resistant Enterobacter cloacae Complex's Colistin Resistance Reversal In Vitro and In Vivo. ACS Infect Dis 2024; 10:662-675. [PMID: 38294410 DOI: 10.1021/acsinfecdis.3c00526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
The Enterobacter cloacae complex (ECC) is a group of nosocomial pathogens that pose a challenge in clinical treatment due to its intrinsic resistance and the ability to rapidly acquire resistance. Colistin was reconsidered as a last-resort antibiotic for combating multidrug-resistant ECC. However, the persistent emergence of colistin-resistant (COL-R) pathogens impedes its clinical efficacy, and novel treatment options are urgently needed. We propose that azomycin, in combination with colistin, restores the susceptibility of COL-R ECC to colistin in vivo and in vitro. Results from the checkerboard susceptibility, time-killing, and live/dead bacterial cell viability tests showed strong synergistic antibacterial activity in vitro. Animal infection models suggested that azomycin-colistin enhanced the survival rate of infected Galleria mellonella and reduced the bacterial load in the thighs of infected mice, highlighting its superior in vivo synergistic antibacterial activity. Crystal violet staining and scanning electron microscopy unveiled the in vitro synergistic antibiofilm effects of azomycin-colistin. The safety of azomycin and azomycin-colistin at experimental concentrations was confirmed through cytotoxicity tests and an erythrocyte hemolysis test. Azomycin-colistin stimulated the production of reactive oxygen species in COL-R ECC and inhibited the PhoPQ two-component system to combat bacterial growth. Thus, azomycin is feasible as a colistin adjuvant against COL-R ECC infection.
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Affiliation(s)
- Panjie Hu
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Huanchang Chen
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Deyi Zhao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Zhexiao Ma
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Weiliang Zeng
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Yijia Han
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Tieli Zhou
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Jianming Cao
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou 325035, Zhejiang, China
| | - Mo Shen
- Department of Clinical Laboratory, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
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2
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Fan C, Zhou F, Huang W, Xue Y, Xu C, Zhang R, Xian M, Feng X. Characterization of an efficient N-oxygenase from Saccharothrix sp. and its application in the synthesis of azomycin. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:194. [PMID: 38104149 PMCID: PMC10724926 DOI: 10.1186/s13068-023-02446-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND The nitro group constitutes a significant functional moiety within numerous valuable substances, such as nitroimidazoles, a class of antimicrobial drugs exhibiting broad spectrum activity. Conventional chemical methods for synthesizing nitro compounds suffer from harsh conditions, multiple steps, and environmental issues. Biocatalysis has emerged as a promising alternative to overcome these drawbacks, with certain enzymes capable of catalyzing nitro group formation gradually being discovered in nature. Nevertheless, the practical application is hindered by the restricted diversity and low catalytic activity exhibited by the reported nitrifying enzymes. RESULTS A novel N-oxygenase SaRohS harboring higher catalytic capability of transformation 2-aminoimidazole to azomycin was characterized from Saccharothrix sp. Phylogenetic tree analysis revealed that SaRohS belongs to the heme-oxygenase-like diiron oxygenase (HDOs) family. SaRohS exhibited optimal activity at pH 5.5 and 25 ℃, respectively. The enzyme maintained relatively stable activity within the pH range of 4.5 to 6.5 and the temperature range of 20 ℃ to 35 ℃. Following sequence alignment and structural analysis, several promising amino acid residues were meticulously chosen for catalytic performance evaluation. Site-directed mutations showed that threonine 75 was essential for the catalytic activity. The dual mutant enzyme G95A/K115T exhibited the highest catalytic efficiency, which was approximately 5.8-fold higher than that of the wild-type and 22.3-fold higher than that of the reported N-oxygenase KaRohS from Kitasatospora azatica. The underlying catalytic mechanism was investigated through molecular docking and molecular dynamics. Finally, whole-cell biocatalysis was performed and 2-aminoimidazole could be effectively converted into azomycin with a reaction conversion rate of 42% within 14 h. CONCLUSIONS An efficient N-oxygenase that catalyzes 2-aminoimidazole to azomycin was screened form Saccharothrix sp., its phylogenetics and enzymatic properties were analyzed. Through site-directed mutation, enhancements in catalytic competence were achieved, and the molecular basis underlying the enhanced enzymatic activity of the mutants was revealed via molecular docking and dynamic simulation. Furthermore, the application potential of this enzyme was assessed through whole cell biocatalysis, demonstrating it as a promising alternative method for azomycin production.
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Affiliation(s)
- Chuanle Fan
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Fang Zhou
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Wei Huang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Yi Xue
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Chao Xu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Rubing Zhang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- Shandong Energy Institute, Qingdao, 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
- Shandong Energy Institute, Qingdao, 266101, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China.
| | - Xinjun Feng
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China.
- Shandong Energy Institute, Qingdao, 266101, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, China.
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3
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Phan HN, Manley OM, Skirboll SS, Cha L, Hilovsky D, Chang WC, Thompson PM, Liu X, Makris TM. Excision of a Protein-Derived Amine for p-Aminobenzoate Assembly by the Self-Sacrificial Heterobimetallic Protein CADD. Biochemistry 2023; 62:3276-3282. [PMID: 37936269 DOI: 10.1021/acs.biochem.3c00406] [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] [Indexed: 11/09/2023]
Abstract
Chlamydia protein associating with death domains (CADD), the founding member of a recently discovered class of nonheme dimetal enzymes termed hemeoxygenase-like dimetaloxidases (HDOs), plays an indispensable role in pathogen survival. CADD orchestrates the biosynthesis of p-aminobenzoic acid (pABA) for integration into folate via the self-sacrificial excision of a protein-derived tyrosine (Tyr27) and several additional processing steps, the nature and timing of which have yet to be fully clarified. Nuclear magnetic resonance (NMR) and proteomics approaches reveal the source and probable timing of amine installation by a neighboring lysine (Lys152). Turnover studies using limiting O2 have identified a para-aminobenzaldehyde (pABCHO) metabolic intermediate that is formed on the path to pABA formation. The use of pABCHO and other probe substrates shows that the heterobimetallic Fe/Mn form of the enzyme is capable of oxygen insertion to generate the pABA-carboxylate.
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Affiliation(s)
- Han N Phan
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Olivia M Manley
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Sydney S Skirboll
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Lide Cha
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Dalton Hilovsky
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Wei-Chen Chang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Peter M Thompson
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- The Molecular Education, Technology and Research Innovation Center (METRIC), North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Xiaojing Liu
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Thomas M Makris
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
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4
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Li H, Huang JW, Dai L, Zheng H, Dai S, Zhang Q, Yao L, Yang Y, Yang Y, Min J, Guo RT, Chen CC. The structural and functional investigation into an unusual nitrile synthase. Nat Commun 2023; 14:7425. [PMID: 37973794 PMCID: PMC10654658 DOI: 10.1038/s41467-023-43285-0] [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: 06/30/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023] Open
Abstract
The biosynthesis of neurotoxin aetokthonotoxin (AETX) that features a unique structure of pentabrominated biindole nitrile involves a first-of-its-kind nitrile synthase termed AetD, an enzyme that shares very low sequence identity to known structures and catalyzes an unprecedented mechanism. In this study, we resolve the crystal structure of AetD in complex with the substrate 5,7-di-Br-L-Trp. AetD adopts the heme oxygenase like fold and forms a hydrophobic cavity within a helical bundle to accommodate the indole moiety. A diiron cluster comprising two irons that serves as a catalytic center binds to the carboxyl O and the amino N of the substrate. Notably, we demonstrate that the AetD-catalyzed reaction is independent of the bromination of the substrate and also solved crystal structures of AetD in complex with 5-Br-L-Trp and L-Trp. Altogether, the present study reveals the substrate-binding pattern and validates the diiron cluster-comprising active center of AetD, which should provide important basis to support the mechanistic investigations into this class of nitrile synthase.
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Affiliation(s)
- Hao Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Jian-Wen Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Longhai Dai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Haibin Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Si Dai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Qishan Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Licheng Yao
- Hubei Gongtong Steroid Drug Research Institute, Wuhan, 430073, PR China
| | - Yunyun Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Yu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Jian Min
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China
| | - Rey-Ting Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China.
- Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, 311121, PR China.
| | - Chun-Chi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, Wuhan, 430062, PR China.
- Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, 311121, PR China.
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5
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Adak S, Ye N, Calderone LA, Schäfer RJB, Lukowski AL, Pandelia ME, Drennan CL, Moore BS. Oxidative rearrangement of tryptophan to indole nitrile by a single diiron enzyme. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.03.551874. [PMID: 37577561 PMCID: PMC10418191 DOI: 10.1101/2023.08.03.551874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Nitriles are uncommon in nature and are typically constructed from oximes via the oxidative decarboxylation of amino acid substrates or from the derivatization of carboxylic acids. Here we report a third strategy of nitrile biosynthesis featuring the cyanobacterial nitrile synthase AetD. During the biosynthesis of the 'eagle-killing' neurotoxin, aetokthonotoxin, AetD converts the alanyl side chain of 5,7-dibromo-L-tryptophan to a nitrile. Employing a combination of structural, biochemical, and biophysical techniques, we characterized AetD as a non-heme diiron enzyme that belongs to the emerging Heme Oxygenase-like Diiron Oxidase and Oxygenase (HDO) superfamily. High-resolution crystal structures of AetD together with the identification of catalytically relevant products provide mechanistic insights into how AetD affords this unique transformation that we propose proceeds via an aziridine intermediate. Our work presents a new paradigm for nitrile biogenesis and portrays a substrate binding and metallocofactor assembly mechanism that may be shared among other HDO enzymes.
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Affiliation(s)
- Sanjoy Adak
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - Naike Ye
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239, United States
| | - Logan A. Calderone
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Rebecca J. B. Schäfer
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - April L. Lukowski
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - Maria-Eirini Pandelia
- Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02453, United States
| | - Catherine L. Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239, United States
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239, United States
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239, United States
| | - Bradley S. Moore
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, California 92093, United States
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6
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Melkonian TR, Vuksanovic N, Silvaggi NR. Probing mechanistic questions in the PLP- and O 2-dependent l-Arg oxidases. Methods Enzymol 2023; 685:493-529. [PMID: 37245913 DOI: 10.1016/bs.mie.2023.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The pyridoxal-5'-phosphate-dependent l-Arg oxidases are unusual in that they are able to catalyze 4-electron oxidations of arginine using only the PLP cofactor. No metals or other accessory cosubstrates are involved; only arginine, dioxygen, and PLP. The catalytic cycles of these enzymes are replete with colored intermediates whose accumulation and decay can be monitored spectrophotometrically. This makes the l-Arg oxidases excellent subjects for detailed mechanistic investigations. They are worth studying, because they can teach us much about how PLP-dependent enzymes modulate the cofactor (structure-function-dynamics) and how new activities can arise from existing enzyme scaffolds. Herein we describe a series of experiments that can be used to probe the mechanisms of l-Arg oxidases. These methods by no means originated in our lab but were learned from talented researchers in other enzyme fields (flavoenzymes and Fe(II)-dependent oxygenases) and have been adapted to fit the requirements of our system. We present practical information for expressing and purifying the l-Arg oxidases, protocols for running stopped-flow experiments to examine the reactions with l-Arg and with dioxygen, and a tandem mass spectrometry-based quench-flow assay to follow the accumulation of the products of the hydroxylating l-Arg oxidases.
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Affiliation(s)
- Trevor R Melkonian
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | | | - Nicholas R Silvaggi
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States.
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7
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Wooldridge R, Stone S, Pedraza A, Ray WK, Helm RF, Allen KD. The Chlamydia trachomatis p-aminobenzoate synthase CADD is a manganese-dependent oxygenase that uses its own amino acid residues as substrates. FEBS Lett 2023; 597:557-572. [PMID: 36647787 DOI: 10.1002/1873-3468.14573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Revised: 12/28/2022] [Accepted: 01/02/2023] [Indexed: 01/18/2023]
Abstract
CADD (chlamydia protein associating with death domains) is a p-aminobenzoate (pAB) synthase involved in a noncanonical route for tetrahydrofolate biosynthesis in Chlamydia trachomatis. Although previously implicated to employ a diiron cofactor, here, we show that pAB synthesis by CADD requires manganese and the physiological cofactor is most likely a heterodinuclear Mn/Fe cluster. Isotope-labeling experiments revealed that the two oxygen atoms in the carboxylic acid portion of pAB are derived from molecular oxygen. Further, mass spectrometry-based proteomic analyses of CADD-derived peptides demonstrated a glycine substitution at Tyr27, providing strong evidence that this residue is sacrificed for pAB synthesis. Additionally, Lys152 was deaminated and oxidized to aminoadipic acid, supporting its proposed role as a sacrificial amino group donor.
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Affiliation(s)
| | - Spenser Stone
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
| | - Andrew Pedraza
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
| | - W Keith Ray
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
| | - Richard F Helm
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
| | - Kylie D Allen
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, USA
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8
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McBride MJ, Pope SR, Nair MA, Sil D, Salas-Solá XE, Krebs C, Martin Bollinger J, Boal AK. Methods for Biophysical Characterization of SznF, a Member of the Heme-Oxygenase-Like Diiron Oxidase/Oxygenase Superfamily. Methods Mol Biol 2023; 2648:123-154. [PMID: 37039989 DOI: 10.1007/978-1-0716-3080-8_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Nonheme diiron enzymes harness the chemical potential of oxygen to catalyze challenging reactions in biology. In their resting state, these enzymes have a diferrous cofactor that is coordinated by histidine and carboxylate ligands. Upon exposure to oxygen, the cofactor oxidizes to its diferric state forming a peroxo- adduct, capable of catalyzing a wide range of oxidative chemistries such as desaturation and heteroatom oxidation. Despite their versatility and prowess, an emerging subset of nonheme diiron enzymes has inherent cofactor instability making them resistant to structural characterization. This feature is widespread among members of the heme-oxygenase-like diiron oxidase/oxygenase (HDO) superfamily. HDOs have a flexible core structure that remodels upon metal binding. Although ~9600 HDOs have been unearthed, few have undergone functional characterization to date. In this chapter, we describe the methods that have been used to characterize the HDO N-oxygenase, SznF. We demonstrate the overexpression and purification of apo-SznF and methodology specifically designed to aid in obtaining an X-ray structure of holo-SznF. We also describe the characterization of the transient SznF-peroxo-Fe(III)2 complex by stopped-flow absorption and Mössbauer spectroscopies. These studies provide the framework for the characterization of new members of the HDO superfamily.
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Affiliation(s)
- Molly J McBride
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Sarah R Pope
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Mrutyunjay A Nair
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Debangsu Sil
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Xavier E Salas-Solá
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - J Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Amie K Boal
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA.
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA.
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9
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Ushimaru R, Abe I. Unusual Dioxygen-Dependent Reactions Catalyzed by Nonheme Iron Enzymes in Natural Product Biosynthesis. ACS Catal 2022. [DOI: 10.1021/acscatal.2c05247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Richiro Ushimaru
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- ACT-X, Japan Science and Technology Agency (JST), Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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10
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Hu WY, Li K, Weitz A, Wen A, Kim H, Murray JC, Cheng R, Chen B, Naowarojna N, Grinstaff MW, Elliott SJ, Chen JS, Liu P. Light-Driven Oxidative Demethylation Reaction Catalyzed by a Rieske-Type Non-heme Iron Enzyme Stc2. ACS Catal 2022; 12:14559-14570. [PMID: 37168530 PMCID: PMC10168674 DOI: 10.1021/acscatal.2c04232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Rieske-type non-heme iron oxygenases/oxidases catalyze a wide range of transformations. Their applications in bioremediation or biocatalysis face two key barriers: the need of expensive NAD(P)H as a reductant and a proper reductase to mediate the electron transfer from NAD(P)H to the oxygenases. To bypass the need of both the reductase and NAD(P)H, using Rieske-type oxygenase (Stc2) catalyzed oxidative demethylation as the model system, we report Stc2 photocatalysis using eosin Y/sulfite as the photosensitizer/sacrificial reagent pair. In a flow-chemistry setting to separate the photo-reduction half-reaction and oxidation half-reaction, Stc2 photo-biocatalysis outperforms the Stc2-NAD(P)H-reductase (GbcB) system. In addition, in a few other selected Rieske enzymes (NdmA, CntA, and GbcA), and a flavin-dependent enzyme (iodotyrosine deiodinase, IYD), the eosin Y/sodium sulfite photo-reduction pair could also serve as the NAD(P)H-reductase surrogate to support catalysis, which implies the potential applicability of this photo-reduction system to other redox enzymes.
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Affiliation(s)
- Wei-Yao Hu
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Kelin Li
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Andrew Weitz
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Aiwen Wen
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Hyomin Kim
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Jessica C. Murray
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Ronghai Cheng
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Baixiong Chen
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Nathchar Naowarojna
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Mark W. Grinstaff
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Sean J. Elliott
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
| | - Jie-Sheng Chen
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai200240, P. R. China
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, Massachusetts02215, United States
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11
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Self-sacrificial tyrosine cleavage by an Fe:Mn oxygenase for the biosynthesis of para-aminobenzoate in Chlamydia trachomatis. Proc Natl Acad Sci U S A 2022; 119:e2210908119. [PMID: 36122239 PMCID: PMC9522330 DOI: 10.1073/pnas.2210908119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chlamydia protein associating with death domains (CADD) is involved in the biosynthesis of para-aminobenzoate (pABA), an essential component of the folate cofactor that is required for the survival and proliferation of the human pathogen Chlamydia trachomatis. The pathway used by Chlamydiae for pABA synthesis differs from the canonical multi-enzyme pathway used by most bacteria that relies on chorismate as a metabolic precursor. Rather, recent work showed pABA formation by CADD derives from l-tyrosine. As a member of the emerging superfamily of heme oxygenase-like diiron oxidases (HDOs), CADD was proposed to use a diiron cofactor for catalysis. However, we report maximal pABA formation by CADD occurs upon the addition of both iron and manganese, which implicates a heterobimetallic Fe:Mn cluster is the catalytically active form. Isotopic labeling experiments and proteomics studies show that CADD generates pABA from a protein-derived tyrosine (Tyr27), a residue that is ∼14 Å from the dimetal site. We propose that this self-sacrificial reaction occurs through O2 activation by a probable Fe:Mn cluster through a radical relay mechanism that connects to the "substrate" Tyr, followed by amination and direct oxygen insertion. These results provide the molecular basis for pABA formation in C. trachomatis, which will inform the design of novel therapeutics.
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12
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McBride MJ, Nair MA, Sil D, Slater JW, Neugebauer M, Chang MCY, Boal AK, Krebs C, Bollinger JM. Substrate-Triggered μ-Peroxodiiron(III) Intermediate in the 4-Chloro-l-Lysine-Fragmenting Heme-Oxygenase-like Diiron Oxidase (HDO) BesC: Substrate Dissociation from, and C4 Targeting by, the Intermediate. Biochemistry 2022; 61:689-702. [PMID: 35380785 PMCID: PMC9047515 DOI: 10.1021/acs.biochem.1c00774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The enzyme BesC from the β-ethynyl-l-serine biosynthetic pathway in Streptomyces cattleya fragments 4-chloro-l-lysine (produced from l-Lysine by BesD) to ammonia, formaldehyde, and 4-chloro-l-allylglycine and can analogously fragment l-Lys itself. BesC belongs to the emerging family of O2-activating non-heme-diiron enzymes with the "heme-oxygenase-like" protein fold (HDOs). Here, we show that the binding of l-Lys or an analogue triggers capture of O2 by the protein's diiron(II) cofactor to form a blue μ-peroxodiiron(III) intermediate analogous to those previously characterized in two other HDOs, the olefin-installing fatty acid decarboxylase, UndA, and the guanidino-N-oxygenase domain of SznF. The ∼5- and ∼30-fold faster decay of the intermediate in reactions with 4-thia-l-Lys and (4RS)-chloro-dl-lysine than in the reaction with l-Lys itself and the primary deuterium kinetic isotope effects (D-KIEs) on decay of the intermediate and production of l-allylglycine in the reaction with 4,4,5,5-[2H4]-l-Lys suggest that the peroxide intermediate or a reversibly connected successor complex abstracts a hydrogen atom from C4 to enable olefin formation. Surprisingly, the sluggish substrate l-Lys can dissociate after triggering intermediate formation, thereby allowing one of the better substrates to bind and react. The structure of apo BesC and the demonstrated linkage between Fe(II) and substrate binding suggest that the triggering event involves an induced ordering of ligand-providing helix 3 (α3) of the conditionally stable HDO core. As previously suggested for SznF, the dynamic α3 also likely initiates the spontaneous degradation of the diiron(III) product cluster after decay of the peroxide intermediate, a trait emerging as characteristic of the nascent HDO family.
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Affiliation(s)
- Molly J. McBride
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Mrutyunjay A. Nair
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Debangsu Sil
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jeffrey W. Slater
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Monica Neugebauer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
- Present address: Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Michelle C. Y. Chang
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, USA
- Departments of Chemistry and of Molecular and Cell Biology, University of California, Berkeley, and Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Amie K. Boal
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Carsten Krebs
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - J. Martin Bollinger
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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13
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He HY, Niikura H, Du YL, Ryan KS. Synthetic and biosynthetic routes to nitrogen-nitrogen bonds. Chem Soc Rev 2022; 51:2991-3046. [PMID: 35311838 DOI: 10.1039/c7cs00458c] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The nitrogen-nitrogen bond is a core feature of diverse functional groups like hydrazines, nitrosamines, diazos, and pyrazoles. Such functional groups are found in >300 known natural products. Such N-N bond-containing functional groups are also found in significant percentage of clinical drugs. Therefore, there is wide interest in synthetic and enzymatic methods to form nitrogen-nitrogen bonds. In this review, we summarize synthetic and biosynthetic approaches to diverse nitrogen-nitrogen-bond-containing functional groups, with a focus on biosynthetic pathways and enzymes.
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Affiliation(s)
- Hai-Yan He
- Department of Chemistry, University of British Columbia, Vancouver, Canada. .,Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China.
| | - Haruka Niikura
- Department of Chemistry, University of British Columbia, Vancouver, Canada.
| | - Yi-Ling Du
- Institute of Pharmaceutical Biotechnology, Zhejiang University School of Medicine, Hangzhou, China
| | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, Canada.
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14
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Li X, Shimaya R, Dairi T, Chang WC, Ogasawara Y. Identification of Cyclopropane Formation in the Biosyntheses of Hormaomycins and Belactosins: Sequential Nitration and Cyclopropanation by Metalloenzymes. Angew Chem Int Ed Engl 2022; 61:e202113189. [PMID: 34904348 PMCID: PMC8810744 DOI: 10.1002/anie.202113189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Indexed: 11/07/2022]
Abstract
Hormaomycins and belactosins are peptide natural products that contain unusual cyclopropane moieties. Bioinformatics analysis of the corresponding biosynthetic gene clusters showed that two conserved genes, hrmI/belK and hrmJ/belL, were potential candidates for catalyzing cyclopropanation. Using in vivo and in vitro assays, the functions of HrmI/BelK and HrmJ/BelL were established. HrmI and BelK, which are heme oxygenase-like dinuclear iron enzymes, catalyze oxidation of the ϵ-amino group of l-lysine to afford l-6-nitronorleucine. Subsequently, HrmJ and BelL, which are iron- and α-ketoglutarate-dependent oxygenases, effectively convert l-6-nitronorleucine into 3-(trans-2-nitrocyclopropyl)-alanine through C4-C6 bond installation. These observations disclose a novel pathway of cyclopropane ring construction and exemplify the new chemistry involving metalloenzymes in natural product biosynthesis.
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Affiliation(s)
- Xiaojun Li
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695 (USA)
| | - Ryo Shimaya
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)
| | - Tohru Dairi
- Graduate School of Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)
| | - Wei-chen Chang
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695 (USA)
| | - Yasushi Ogasawara
- Graduate School of Engineering, Hokkaido University, N13 W8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)
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15
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Li X, Shimaya R, Dairi T, Chang W, Ogasawara Y. Identification of Cyclopropane Formation in the Biosyntheses of Hormaomycins and Belactosins: Sequential Nitration and Cyclopropanation by Metalloenzymes. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202113189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Xiaojun Li
- Department of Chemistry North Carolina State University 2620 Yarbrough Drive Raleigh NC 27695 USA
| | - Ryo Shimaya
- Graduate School of Chemical Sciences and Engineering Hokkaido University N13W8, Kita-ku Sapporo Hokkaido 060-8628 Japan
| | - Tohru Dairi
- Graduate School of Engineering Hokkaido University N13W8, Kita-ku Sapporo Hokkaido 060-8628 Japan
| | - Wei‐chen Chang
- Department of Chemistry North Carolina State University 2620 Yarbrough Drive Raleigh NC 27695 USA
| | - Yasushi Ogasawara
- Graduate School of Engineering Hokkaido University N13W8, Kita-ku Sapporo Hokkaido 060-8628 Japan
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16
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Tang Z, Tang H, Wang W, Xue Y, Chen D, Tang W, Liu W. Biosynthesis of a New Fusaoctaxin Virulence Factor in Fusarium graminearum Relies on a Distinct Path To Form a Guanidinoacetyl Starter Unit Priming Nonribosomal Octapeptidyl Assembly. J Am Chem Soc 2021; 143:19719-19730. [PMID: 34784713 DOI: 10.1021/jacs.1c07770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Fusarium graminearum is a pathogenic fungus causing huge economic losses worldwide via crop infection leading to yield reduction and grain contamination. The process through which the fungal invasion occurs remains poorly understood. We recently characterized fusaoctaxin A in F. graminearum, where this octapeptide virulence factor results from an assembly line encoded in fg3_54, a gene cluster proved to be involved in fungal pathogenicity and host adaptation. Focusing on genes in this cluster that are related to fungal invasiveness but not to the biosynthesis of fusaoctaxin A, we here report the identification and characterization of fusaoctaxin B, a new octapeptide virulence factor with comparable activity in wheat infection. Fusaoctaxin B differs from fusaoctaxin A at the N-terminus by possessing a guanidinoacetic acid (GAA) unit, formation of which depends on the combined activities of the protein products of fgm1-3. Fgm1 is a cytochrome P450 protein that oxygenates l-Arg to 4(R)-hydroxyl-l-Arg in a regio- and stereoselective manner. Then, Cβ-Cγ bond cleavage proceeds in the presence of Fgm3, a pyridoxal-5'-phosphate-dependent lyase, giving guanidinoacetaldehyde and l-Ala. Rather than being directly oxidized to GAA, the guanidine-containing aldehyde undergoes spontaneous cyclization and subsequent enzymatic dehydrogenation to provide glycociamidine, which is linearized by Fgm2, a metallo-dependent amidohydrolase. The GAA path in F. graminearum is distinct from that previously known to involve l-Arg:l-Gly aminidotransferase activity. To provide this nonproteinogenic starter unit that primes nonribosomal octapeptidyl assembly, F. graminearum employs new chemistry to process l-Arg through inert C-H bond activation, selective C-C bond cleavage, cyclization-based alcohol dehydrogenation, and amidohydrolysis-associated linearization.
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Affiliation(s)
- Zhijun Tang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Haoyu Tang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Wanqiu Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Yufeng Xue
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Dandan Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Weihua Tang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China
| | - Wen Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.,Huzhou Center of Bio-Synthetic Innovation, 1366 Hongfeng Road, Huzhou 313000, China
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17
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Shimo S, Ushimaru R, Engelbrecht A, Harada M, Miyamoto K, Kulik A, Uchiyama M, Kaysser L, Abe I. Stereodivergent Nitrocyclopropane Formation during Biosynthesis of Belactosins and Hormaomycins. J Am Chem Soc 2021; 143:18413-18418. [PMID: 34710328 DOI: 10.1021/jacs.1c10201] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Belactosins and hormaomycins are peptide natural products containing 3-(2-aminocyclopropyl)alanine and 3-(2-nitrocyclopropyl)alanine residues, respectively, with opposite stereoconfigurations of the cyclopropane ring. Herein we demonstrate that the heme oxygenase-like enzymes BelK and HrmI catalyze the N-oxygenation of l-lysine to generate 6-nitronorleucine. The nonheme iron enzymes BelL and HrmJ then cyclize the nitroalkane moiety to the nitrocyclopropane ring with the desired stereochemistry found in the corresponding natural products. We also show that both cyclopropanases remove the 4-proS-H of 6-nitronorleucine during the cyclization, establishing the inversion and retention of the configuration at C4 during the BelL and HrmJ reactions, respectively. This study reveals the unique strategy for stereocontrolled cyclopropane synthesis in nature.
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Affiliation(s)
- Shotaro Shimo
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Richiro Ushimaru
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,ACT-X, Japan Science and Technology Agency (JST), Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Alicia Engelbrecht
- Pharmaceutical Institute, Department of Pharmaceutical Biology, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Mei Harada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazunori Miyamoto
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Andreas Kulik
- Interfaculty Institute of Microbiology and Infection Medicine (IMIT), University of Tübingen, 72076 Tübingen, Germany
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,Research Initiative for Supra-Materials (RISM), Shinshu University, Ueda, 386-8567, Japan
| | - Leonard Kaysser
- Institute for Drug Discovery, Department of Pharmaceutical Biology, University of Leipzig, Eilenburger Str. 14, 04317 Leipzig, Germany
| | - Ikuro Abe
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.,Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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18
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A shared mechanistic pathway for pyridoxal phosphate-dependent arginine oxidases. Proc Natl Acad Sci U S A 2021; 118:2012591118. [PMID: 34580201 DOI: 10.1073/pnas.2012591118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023] Open
Abstract
The mechanism by which molecular oxygen is activated by the organic cofactor pyridoxal phosphate (PLP) for oxidation reactions remains poorly understood. Recent work has identified arginine oxidases that catalyze desaturation or hydroxylation reactions. Here, we investigate a desaturase from the Pseudoalteromonas luteoviolacea indolmycin pathway. Our work, combining X-ray crystallographic, biochemical, spectroscopic, and computational studies, supports a shared mechanism with arginine hydroxylases, involving two rounds of single-electron transfer to oxygen and superoxide rebound at the 4' carbon of the PLP cofactor. The precise positioning of a water molecule in the active site is proposed to control the final reaction outcome. This proposed mechanism provides a unified framework to understand how oxygen can be activated by PLP-dependent enzymes for oxidation of arginine and elucidates a shared mechanistic pathway and intertwined evolutionary history for arginine desaturases and hydroxylases.
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19
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Structure and assembly of the diiron cofactor in the heme-oxygenase-like domain of the N-nitrosourea-producing enzyme SznF. Proc Natl Acad Sci U S A 2021; 118:2015931118. [PMID: 33468680 PMCID: PMC7848743 DOI: 10.1073/pnas.2015931118] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The enzyme SznF assembles the N-nitrosourea pharmacophore of the drug streptozotocin. Its N-oxygenase domain resembles heme-oxygenase (HO) and belongs to an emerging superfamily of HO-like diiron enzymes (HDOs) with unstable metallocofactors that have resisted structural characterization. Insight into cofactor dynamics from our prior investigation of SznF’s N-oxygenation reactions suggested an approach that has yielded a structure of a functionally assigned HDO with its diiron cofactor intact. Conformational changes accompanying cofactor (dis)assembly explain its instability, and the observation of an unanticipated glutamate ligand that is conserved in only a subset of HDO sequences provides a potential basis for top-level assignment of enzymatic function. Our results thus provide a roadmap for structural and functional characterization of novel HDOs. In biosynthesis of the pancreatic cancer drug streptozotocin, the tridomain nonheme-iron oxygenase SznF hydroxylates Nδ and Nω′ of Nω-methyl-l-arginine before oxidatively rearranging the triply modified guanidine to the N-methyl-N-nitrosourea pharmacophore. A previously published structure visualized the monoiron cofactor in the enzyme’s C-terminal cupin domain, which promotes the final rearrangement, but exhibited disorder and minimal metal occupancy in the site of the proposed diiron cofactor in the N-hydroxylating heme-oxygenase–like (HO-like) central domain. We leveraged our recent observation that the N-oxygenating µ-peroxodiiron(III/III) intermediate can form in the HO-like domain after the apo protein self-assembles its diiron(II/II) cofactor to solve structures of SznF with both of its iron cofactors bound. These structures of a biochemically validated member of the emerging heme-oxygenase–like diiron oxidase and oxygenase (HDO) superfamily with intact diiron cofactor reveal both the large-scale conformational change required to assemble the O2-reactive Fe2(II/II) complex and the structural basis for cofactor instability—a trait shared by the other validated HDOs. During cofactor (dis)assembly, a ligand-harboring core helix dynamically (un)folds. The diiron cofactor also coordinates an unanticipated Glu ligand contributed by an auxiliary helix implicated in substrate binding by docking and molecular dynamics simulations. The additional carboxylate ligand is conserved in another N-oxygenating HDO but not in two HDOs that cleave carbon–hydrogen and carbon–carbon bonds to install olefins. Among ∼9,600 sequences identified bioinformatically as members of the emerging HDO superfamily, ∼25% conserve this additional carboxylate residue and are thus tentatively assigned as N-oxygenases.
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20
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Nóbile ML, Stricker AM, Marchesano L, Iribarren AM, Lewkowicz ES. N-oxygenation of amino compounds: Early stages in its application to the biocatalyzed preparation of bioactive compounds. Biotechnol Adv 2021; 51:107726. [PMID: 33675955 DOI: 10.1016/j.biotechadv.2021.107726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 02/25/2021] [Accepted: 02/26/2021] [Indexed: 10/22/2022]
Abstract
Among the compounds that contain unusual functional groups, nitro is perhaps one of the most interesting due to the valuable properties it confers on pharmaceuticals and explosives. Traditional chemistry has for many years used environmentally unfriendly strategies; in contrast, the biocatalyzed production of this type of products offers a promising alternative. The small family of enzymes formed by N-oxygenases allows the conversion of an amino group to a nitro through the sequential addition of oxygen. These enzymes also make it possible to obtain other less oxidized N-O functions, such as hydroxylamine or nitroso, present in intermediate or final products. The current substrates on which these enzymes are reported to work encompass a few aromatic molecules and sugars. The unique characteristics of N-oxygenases and the great economic value of the products that they could generate, place them in a position of very high scientific and industrial interest. The most important and best studied N-oxygenases will be presented here.
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Affiliation(s)
- Matías L Nóbile
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina.
| | - Abigail M Stricker
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Lucas Marchesano
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Adolfo M Iribarren
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
| | - Elizabeth S Lewkowicz
- Universidad Nacional de Quilmes, CONICET, Departamento de Ciencia y Tecnología, Biocatalysis and Biotransformation Laboratory, Roque Sáenz Peña 352, Bernal 1876, Buenos Aires, Argentina
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21
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Oxygen reactivity with pyridoxal 5'-phosphate enzymes: biochemical implications and functional relevance. Amino Acids 2020; 52:1089-1105. [PMID: 32844248 PMCID: PMC7497351 DOI: 10.1007/s00726-020-02885-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/18/2020] [Indexed: 12/29/2022]
Abstract
The versatility of reactions catalyzed by pyridoxal 5'-phosphate (PLP) enzymes is largely due to the chemistry of their extraordinary catalyst. PLP is necessary for many reactions involving amino acids. Reaction specificity is controlled by the orientation of the external aldimine intermediate that is formed upon addition of the amino acidic substrate to the coenzyme. The breakage of a specific bond of the external aldimine gives rise to a carbanionic intermediate. From this point, the different reaction pathways diverge leading to multiple activities: transamination, decarboxylation, racemization, elimination, and synthesis. A significant novelty appeared approximately 30 years ago when it was reported that some PLP-dependent decarboxylases are able to consume molecular oxygen transforming an amino acid into a carbonyl compound. These side paracatalytic reactions could be particularly relevant for human health, also considering that some of these enzymes are responsible for the synthesis of important neurotransmitters such as γ-aminobutyric acid, dopamine, and serotonin, whose dysregulation under oxidative conditions could have important implications in neurodegenerative states. However, the reactivity of PLP enzymes with dioxygen is not confined to mammals/animals. In fact, some plant PLP decarboxylases have been reported to catalyze oxidative reactions producing carbonyl compounds. Moreover, other recent reports revealed the existence of new oxidase activities catalyzed by new PLP enzymes, MppP, RohP, Ind4, CcbF, PvdN, Cap15, and CuaB. These PLP enzymes belong to the bacterial and fungal kingdoms and are present in organisms synthesizing bioactive compounds. These new PLP activities are not paracatalytic and could only scratch the surface on a wider and unexpected catalytic capability of PLP enzymes.
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22
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McBride MJ, Sil D, Ng TL, Crooke AM, Kenney GE, Tysoe CR, Zhang B, Balskus EP, Boal AK, Krebs C, Bollinger JM. A Peroxodiiron(III/III) Intermediate Mediating Both N-Hydroxylation Steps in Biosynthesis of the N-Nitrosourea Pharmacophore of Streptozotocin by the Multi-domain Metalloenzyme SznF. J Am Chem Soc 2020; 142:11818-11828. [PMID: 32511919 DOI: 10.1021/jacs.0c03431] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The alkylating warhead of the pancreatic cancer drug streptozotocin (SZN) contains an N-nitrosourea moiety constructed from Nω-methyl-l-arginine (l-NMA) by the multi-domain metalloenzyme SznF. The enzyme's central heme-oxygenase-like (HO-like) domain sequentially hydroxylates Nδ and Nω' of l-NMA. Its C-terminal cupin domain then rearranges the triply modified arginine to Nδ-hydroxy-Nω-methyl-Nω-nitroso-l-citrulline, the proposed donor of the functional pharmacophore. Here we show that the HO-like domain of SznF can bind Fe(II) and use it to capture O2, forming a peroxo-Fe2(III/III) intermediate. This intermediate has absorption- and Mössbauer-spectroscopic features similar to those of complexes previously trapped in ferritin-like diiron oxidases and oxygenases (FDOs) and, more recently, the HO-like fatty acid oxidase UndA. The SznF peroxo-Fe2(III/III) complex is an intermediate in both hydroxylation steps, as shown by the concentration-dependent acceleration of its decay upon exposure to either l-NMA or Nδ-hydroxy-Nω-methyl-l-Arg (l-HMA). The Fe2(III/III) cluster produced upon decay of the intermediate has a small Mössbauer quadrupole splitting parameter, implying that, unlike the corresponding product states of many FDOs, it lacks an oxo-bridge. The subsequent decomposition of the product cluster to one or more paramagnetic Fe(III) species over several hours explains why SznF was previously purified and crystallographically characterized without its cofactor. Programmed instability of the oxidized form of the cofactor appears to be a unifying characteristic of the emerging superfamily of HO-like diiron oxidases and oxygenases (HDOs).
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Affiliation(s)
| | | | - Tai L Ng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Anne Marie Crooke
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | - Grace E Kenney
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
| | | | | | - Emily P Balskus
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States
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23
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Hoffarth ER, Rothchild KW, Ryan KS. Emergence of oxygen- and pyridoxal phosphate-dependent reactions. FEBS J 2020; 287:1403-1428. [PMID: 32142210 DOI: 10.1111/febs.15277] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 11/29/2019] [Accepted: 03/03/2020] [Indexed: 12/21/2022]
Abstract
Pyridoxal 5'-phosphate (PLP) is an organic cofactor employed by ~ 4% of enzymes. The structure of the PLP cofactor allows for the stabilization of carbanions through resonance. A small number of PLP-dependent enzymes employ molecular oxygen as a cosubstrate. Here, we review the biological roles and possible mechanisms of these enzymes, and we observe that these enzymes are found in multiple protein families, suggesting that reaction with oxygen might have emerged de novo in several protein families and thus could be directed to emerge again through laboratory evolution experiments.
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Affiliation(s)
- Elesha R Hoffarth
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
| | | | - Katherine S Ryan
- Department of Chemistry, University of British Columbia, Vancouver, BC, Canada
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24
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Hill RA, Sutherland A. Hot off the press. Nat Prod Rep 2019. [DOI: 10.1039/c9np90041a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as phlegmadine A from Phlegmariurus phlegmaria.
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