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Kayrouz CM, Ireland KA, Ying VY, Davis KM, Seyedsayamdost MR. Discovery of the selenium-containing antioxidant ovoselenol derived from convergent evolution. Nat Chem 2024:10.1038/s41557-024-01600-2. [PMID: 39143299 DOI: 10.1038/s41557-024-01600-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 07/11/2024] [Indexed: 08/16/2024]
Abstract
Selenium is an essential micronutrient, but its presence in biology has been limited to protein and nucleic acid biopolymers. The recent identification of a biosynthetic pathway for selenium-containing small molecules suggests that there is a larger family of selenometabolites that remains to be discovered. Here we identify a recently evolved branch of abundant and uncharacterized metalloenzymes that we predict are involved in selenometabolite biosynthesis using a bioinformatic search strategy that relies on the mapping of composite active site motifs. Biochemical studies confirm this prediction and show that these enzymes form an unusual C-Se bond onto histidine, thus giving rise to a distinct selenometabolite and potent antioxidant that we have termed ovoselenol. Aside from providing insights into the evolution of this enzyme class and the structural basis of C-Se bond formation, our work offers a blueprint for charting the microbial selenometabolome in the future.
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Affiliation(s)
- Chase M Kayrouz
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | | | - Vanessa Y Ying
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | | | - Mohammad R Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, NJ, USA.
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA.
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2
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Tossounian MA, Zhao Y, Yu BYK, Markey SA, Malanchuk O, Zhu Y, Cain A, Gout I. Low-molecular-weight thiol transferases in redox regulation and antioxidant defence. Redox Biol 2024; 71:103094. [PMID: 38479221 PMCID: PMC10950700 DOI: 10.1016/j.redox.2024.103094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/08/2024] [Accepted: 02/18/2024] [Indexed: 03/24/2024] Open
Abstract
Low-molecular-weight (LMW) thiols are produced in all living cells in different forms and concentrations. Glutathione (GSH), coenzyme A (CoA), bacillithiol (BSH), mycothiol (MSH), ergothioneine (ET) and trypanothione T(SH)2 are the main LMW thiols in eukaryotes and prokaryotes. LMW thiols serve as electron donors for thiol-dependent enzymes in redox-mediated metabolic and signaling processes, protect cellular macromolecules from oxidative and xenobiotic stress, and participate in the reduction of oxidative modifications. The level and function of LMW thiols, their oxidized disulfides and mixed disulfide conjugates in cells and tissues is tightly controlled by dedicated oxidoreductases, such as peroxiredoxins, glutaredoxins, disulfide reductases and LMW thiol transferases. This review provides the first summary of the current knowledge of structural and functional diversity of transferases for LMW thiols, including GSH, BSH, MSH and T(SH)2. Their role in maintaining redox homeostasis in single-cell and multicellular organisms is discussed, focusing in particular on the conjugation of specific thiols to exogenous and endogenous electrophiles, or oxidized protein substrates. Advances in the development of new research tools, analytical methodologies, and genetic models for the analysis of known LMW thiol transferases will expand our knowledge and understanding of their function in cell growth and survival under oxidative stress, nutrient deprivation, and during the detoxification of xenobiotics and harmful metabolites. The antioxidant function of CoA has been recently discovered and the breakthrough in defining the identity and functional characteristics of CoA S-transferase(s) is soon expected.
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Affiliation(s)
- Maria-Armineh Tossounian
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Yuhan Zhao
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Bess Yi Kun Yu
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Samuel A Markey
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Oksana Malanchuk
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom; Department of Cell Signaling, Institute of Molecular Biology and Genetics, Kyiv, 143, Ukraine
| | - Yuejia Zhu
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Amanda Cain
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom
| | - Ivan Gout
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, United Kingdom; Department of Cell Signaling, Institute of Molecular Biology and Genetics, Kyiv, 143, Ukraine.
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3
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Kayrouz CM, Ireland KA, Ying V, Davis KM, Seyedsayamdost MR. Ovoselenol, a Selenium-containing Antioxidant Derived from Convergent Evolution. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588772. [PMID: 38645211 PMCID: PMC11030361 DOI: 10.1101/2024.04.10.588772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Selenium is an essential micronutrient, but its presence in biology has been limited to protein and nucleic acid biopolymers. The recent identification of the first biosynthetic pathway for selenium-containing small molecules suggests that there is a larger family of selenometabolites that remains to be discovered. Using a bioinformatic search strategy that relies on mapping of composite active site motifs, we identify a recently evolved branch of abundant and uncharacterized metalloenzymes that we predict are involved in selenometabolite biosynthesis. Biochemical studies confirm this prediction and show that these enzymes form an unusual C-Se bond onto histidine, thus giving rise to a novel selenometabolite and potent antioxidant that we have termed ovoselenol. Aside from providing insights into the evolution of this enzyme class and the structural basis of C-Se bond formation, our work offers a blueprint for charting the microbial selenometabolome in the future.
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Affiliation(s)
- Chase M. Kayrouz
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
| | - Kendra A. Ireland
- Department of Chemistry, Emory University, Atlanta, GA 30322, United States
| | - Vanessa Ying
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
| | - Katherine M. Davis
- Department of Chemistry, Emory University, Atlanta, GA 30322, United States
| | - Mohammad R. Seyedsayamdost
- Department of Chemistry, Princeton University, Princeton, NJ 08544, United States
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, United States
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4
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Keller LML, Flattich K, Weber-Ban E. Novel WYL domain-containing transcriptional activator acts in response to genotoxic stress in rapidly growing mycobacteria. Commun Biol 2023; 6:1222. [PMID: 38042942 PMCID: PMC10693628 DOI: 10.1038/s42003-023-05592-6] [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: 07/05/2023] [Accepted: 11/15/2023] [Indexed: 12/04/2023] Open
Abstract
The WYL domain is a nucleotide-sensing module that controls the activity of transcription factors involved in the regulation of DNA damage response and phage defense mechanisms in bacteria. In this study, we investigated a WYL domain-containing transcription factor in Mycobacterium smegmatis that we termed stress-involved WYL domain-containing regulator (SiwR). We found that SiwR controls adjacent genes that belong to the DinB/YfiT-like putative metalloenzymes superfamily by upregulating their expression in response to various genotoxic stress conditions, including upon exposure to H2O2 or the natural antibiotic zeocin. We show that SiwR binds different forms of single-stranded DNA (ssDNA) with high affinity, primarily through its characteristic WYL domain. In combination with complementation studies of a M. smegmatis siwR deletion strain, our findings support a role of the WYL domains as signal-sensing activity switches of WYL domain-containing transcription factors (WYL TFs). Our study provides evidence that WYL TFs are involved in the adaptation of bacteria to changing environments and encountered stress conditions.
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Affiliation(s)
| | - Kim Flattich
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Eilika Weber-Ban
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland.
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5
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Jayasinghe YP, Banco MT, Lindenberger JJ, Favrot L, Palčeková Z, Jackson M, Manabe S, Ronning DR. The Mycobacterium tuberculosis mycothiol S-transferase is divalent metal-dependent for mycothiol binding and transfer. RSC Med Chem 2023; 14:491-500. [PMID: 36970142 PMCID: PMC10034076 DOI: 10.1039/d2md00401a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/21/2023] [Indexed: 01/27/2023] Open
Abstract
Mycothiol S-transferase (MST) (encoded by the rv0443 gene) was previously identified as the enzyme responsible for the transfer of Mycothiol (MSH) to xenobiotic acceptors in Mycobacterium tuberculosis (M.tb) during xenobiotic stress. To further characterize the functionality of MST in vitro and the possible roles in vivo, X-ray crystallographic, metal-dependent enzyme kinetics, thermal denaturation studies, and antibiotic MIC determination in rv0433 knockout strain were performed. The binding of MSH and Zn2+ increases the melting temperature by 12.9 °C as a consequence of the cooperative stabilization of MST by both MSH and metal. The co-crystal structure of MST in complex with MSH and Zn2+ to 1.45 Å resolution supports the specific utilization of MSH as a substrate as well as affording insights into the structural requirements of MSH binding and the metal-assisted catalytic mechanism of MST. Contrary to the well-defined role of MSH in mycobacterial xenobiotic responses and the ability of MST to bind MSH, cell-based studies with an M.tb rv0443 knockout strain failed to provide evidence for a role of MST in processing of rifampicin or isoniazid. These studies suggest the necessity of a new direction to identify acceptors of the enzyme and better define the biological role of MST in mycobacteria.
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Affiliation(s)
- Yahani P Jayasinghe
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha Nebraska USA
| | - Michael T Banco
- Department of Chemistry and Biochemistry, University of Toledo Toledo Ohio USA
| | | | - Lorenza Favrot
- Department of Chemistry and Biochemistry, University of Toledo Toledo Ohio USA
| | - Zuzana Palčeková
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University Fort Collins Colorado USA
| | - Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University Fort Collins Colorado USA
| | - Shino Manabe
- Laboratory of Functional Molecule Chemistry, Pharmaceutical Department and Institute of Medicinal Chemistry, Hoshi University Tokyo Japan
- Research Center for Pharmaceutical Development, Graduate School of Pharmaceutical Sciences & Faculty of Pharmaceutical Sciences, Tohoku University Miyagi Japan
| | - Donald R Ronning
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center Omaha Nebraska USA
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6
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The role of low molecular weight thiols in Mycobacterium tuberculosis. Tuberculosis (Edinb) 2019; 116:44-55. [PMID: 31153518 DOI: 10.1016/j.tube.2019.04.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 04/16/2019] [Accepted: 04/22/2019] [Indexed: 02/06/2023]
Abstract
Low molecular weight (LMW) thiols are molecules with a functional sulfhydryl group that enable them to detoxify reactive oxygen species, reactive nitrogen species and other free radicals. Their roles range from their ability to modulate the immune system to their ability to prevent damage of biological molecules such as DNA and proteins by protecting against oxidative, nitrosative and acidic stress. LMW thiols are synthesized and found in both eukaryotes and prokaryotes. Due to their beneficial role to both eukaryotes and prokaryotes, their specific functions need to be elucidated, most especially in pathogenic prokaryotes such as Mycobacterium tuberculosis (M.tb), in order to provide a rationale for targeting their biosynthesis for drug development. Ergothioneine (ERG), mycothiol (MSH) and gamma-glutamylcysteine (GGC) are LMW thiols that have been shown to interplay to protect M.tb against cellular stress. Though ERG, MSH and GGC seem to have overlapping functions, studies are gradually revealing their unique physiological roles. Understanding their unique physiological role during the course of tuberculosis (TB) infection, would pave the way for the development of drugs that target their biosynthetic pathway. This review identifies the knowledge gap in the unique physiological roles of LMW thiols and proposes their mechanistic roles based on previous studies. In addition, it gives an update on identified inhibitors of their biosynthetic enzymes.
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7
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Zhang J, Zhao L, Seo HS, Jung JH, Choi JI, Kim MK, Lim S. Crystal structure of the highly radiation-inducible DinB/YfiT superfamily protein DR0053 from Deinococcus radiodurans R1. Biochem Biophys Res Commun 2019; 513:354-359. [PMID: 30961930 DOI: 10.1016/j.bbrc.2019.03.209] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 03/30/2019] [Indexed: 12/11/2022]
Abstract
Deinococcus radiodurans is an extremophilic bacterium well-known for its extraordinary resistance to ionizing radiation and other DNA damage- and oxidative stress-generating agents. In addition to its efficient DNA damage repair and oxidative stress resistance mechanisms, protein family expansions and stress-induced genes/proteins are also regarded as important components that add to the robustness of this bacterium. D. radiodurans encodes specific expansions of 13 DinB/YfiT homologs, which is a relatively large number when compared to those found in Gram-positive bacteria. In this study, we investigated the expression profiles of 13 dinB genes after γ-irradiation, mitomycin C and H2O2 treatment. dr0053 had the highest expression levels after DNA-damage inducing γ-irradiation and MMC treatment, increasing ∼200-fold and ∼16-fold, respectively. We also determined the crystal structure of DR0053 at 2.07 Å resolution. DR0053 adopted a typical four-helix bundle structure that is characteristic of DinB/YfiT proteins. A putative metal binding site was occupied by zinc even though the highly conserved His triad of DinB/YfiT proteins was replaced by Glu-Asn-His.
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Affiliation(s)
- Jing Zhang
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Biotechnology and Bioengineering, Interdisciplinary Program for Bioenergy and Biomaterials, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Lei Zhao
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Biotechnology and Bioengineering, Interdisciplinary Program for Bioenergy and Biomaterials, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Ho Seong Seo
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Radiation Science and Technology, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Jong-Hyun Jung
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Radiation Science and Technology, University of Science and Technology, Daejeon, 34113, Republic of Korea
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Interdisciplinary Program for Bioenergy and Biomaterials, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Min-Kyu Kim
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Radiation Science and Technology, University of Science and Technology, Daejeon, 34113, Republic of Korea.
| | - Sangyong Lim
- Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, 56212, Republic of Korea; Department of Radiation Science and Technology, University of Science and Technology, Daejeon, 34113, Republic of Korea.
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8
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Tripathi P, Shine EE, Healy AR, Kim CS, Herzon SB, Bruner SD, Crawford JM. ClbS Is a Cyclopropane Hydrolase That Confers Colibactin Resistance. J Am Chem Soc 2017; 139:17719-17722. [PMID: 29112397 DOI: 10.1021/jacs.7b09971] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Certain commensal Escherichia coli contain the clb biosynthetic gene cluster that codes for small molecule prodrugs known as precolibactins. Precolibactins are converted to colibactins by N-deacylation; the latter are postulated to be genotoxic and to contribute to colorectal cancer formation. Though advances toward elucidating (pre)colibactin biosynthesis have been made, the functions and mechanisms of several clb gene products remain poorly understood. Here we report the 2.1 Å X-ray structure and molecular function of ClbS, a gene product that confers resistance to colibactin toxicity in host bacteria and which has been shown to be important for bacterial viability. The structure harbors a potential colibactin binding site and shares similarity to known hydrolases. In vitro studies using a synthetic colibactin analog and ClbS or an active site residue mutant reveal cyclopropane hydrolase activity that converts the electrophilic cyclopropane of the colibactins into an innocuous hydrolysis product. As the cyclopropane has been shown to be essential for genotoxic effects in vitro, this ClbS-catalyzed ring-opening provides a means for the bacteria to circumvent self-induced genotoxicity. Our study provides a molecular-level view of the first reported cyclopropane hydrolase and support for a specific mechanistic role of this enzyme in colibactin resistance.
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Affiliation(s)
- Prabhanshu Tripathi
- Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Emilee E Shine
- Department of Microbial Pathogenesis, Yale School of Medicine , New Haven, Connecticut 06536, United States.,Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States
| | - Alan R Healy
- Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States.,Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Chung Sub Kim
- Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States.,Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
| | - Seth B Herzon
- Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States.,Department of Pharmacology, Yale School of Medicine , New Haven, Connecticut 06520, United States
| | - Steven D Bruner
- Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
| | - Jason M Crawford
- Department of Microbial Pathogenesis, Yale School of Medicine , New Haven, Connecticut 06536, United States.,Chemical Biology Institute, Yale University , West Haven, Connecticut 06516, United States.,Department of Chemistry, Yale University , New Haven, Connecticut 06520, United States
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9
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Metallochaperones and metalloregulation in bacteria. Essays Biochem 2017; 61:177-200. [PMID: 28487396 DOI: 10.1042/ebc20160076] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 12/21/2022]
Abstract
Bacterial transition metal homoeostasis or simply 'metallostasis' describes the process by which cells control the intracellular availability of functionally required metal cofactors, from manganese (Mn) to zinc (Zn), avoiding both metal deprivation and toxicity. Metallostasis is an emerging aspect of the vertebrate host-pathogen interface that is defined by a 'tug-of-war' for biologically essential metals and provides the motivation for much recent work in this area. The host employs a number of strategies to starve the microbial pathogen of essential metals, while for others attempts to limit bacterial infections by leveraging highly competitive metals. Bacteria must be capable of adapting to these efforts to remodel the transition metal landscape and employ highly specialized metal sensing transcriptional regulators, termed metalloregulatory proteins,and metallochaperones, that allocate metals to specific destinations, to mediate this adaptive response. In this essay, we discuss recent progress in our understanding of the structural mechanisms and metal specificity of this adaptive response, focusing on energy-requiring metallochaperones that play roles in the metallocofactor active site assembly in metalloenzymes and metallosensors, which govern the systems-level response to metal limitation and intoxication.
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10
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Goncharenko KV, Vit A, Blankenfeldt W, Seebeck FP. Struktur der Sulfoxid-Synthase EgtB aus der Ergothionein- Biosynthese. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410045] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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11
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Goncharenko KV, Vit A, Blankenfeldt W, Seebeck FP. Structure of the sulfoxide synthase EgtB from the ergothioneine biosynthetic pathway. Angew Chem Int Ed Engl 2015; 54:2821-4. [PMID: 25597398 DOI: 10.1002/anie.201410045] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Indexed: 01/09/2023]
Abstract
The non-heme iron enzyme EgtB catalyzes O2 -dependent C-S bond formation between γ-glutamyl cysteine and N-α-trimethyl histidine as the central step in ergothioneine biosynthesis. Both, the catalytic activity and the architecture of EgtB are distinct from known sulfur transferases or thiol dioxygenases. The crystal structure of EgtB from Mycobacterium thermoresistibile in complex with γ-glutamyl cysteine and N-α-trimethyl histidine reveals that the two substrates and three histidine residues serve as ligands in an octahedral iron binding site. This active site geometry is consistent with a catalytic mechanism in which C-S bond formation is initiated by an iron(III)-complexed thiyl radical attacking the imidazole ring of N-α-trimethyl histidine.
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Affiliation(s)
- Kristina V Goncharenko
- Department for Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel (Switzerland)
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12
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Perera VR, Newton GL, Parnell JM, Komives EA, Pogliano K. Purification and characterization of the Staphylococcus aureus bacillithiol transferase BstA. BIOCHIMICA ET BIOPHYSICA ACTA 2014; 1840:2851-61. [PMID: 24821014 PMCID: PMC4802972 DOI: 10.1016/j.bbagen.2014.05.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/30/2014] [Accepted: 05/02/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Gram-positive bacteria in the phylum Firmicutes synthesize the low molecular weight thiol bacillithiol rather than glutathione or mycothiol. The bacillithiol transferase YfiT from Bacillus subtilis was identified as a new member of the recently discovered DinB/YfiT-like Superfamily. Based on structural similarity using the Superfamily program, we have determined 30 of 31 Staphylococcus aureus strains encode a single bacillithiol transferase from the DinB/YfiT-like Superfamily, while the remaining strain encodes two proteins. METHODS We have cloned, purified, and confirmed the activity of a recombinant bacillithiol transferase (henceforth called BstA) encoded by the S. aureus Newman ORF NWMN_2591. Moreover, we have studied the saturation kinetics and substrate specificity of this enzyme using in vitro biochemical assays. RESULTS BstA was found to be active with the co-substrate bacillithiol, but not with other low molecular weight thiols tested. BstA catalyzed bacillithiol conjugation to the model substrates monochlorobimane, 1-chloro-2,4-dinitrobenzene, and the antibiotic cerulenin. Several other molecules, including the antibiotic rifamycin S, were found to react directly with bacillithiol, but the addition of BstA did not enhance the rate of reaction. Furthermore, cells growing in nutrient rich medium exhibited low BstA activity. CONCLUSIONS BstA is a bacillithiol transferase from S. aureus that catalyzes the detoxification of cerulenin. Additionally, we have determined that bacillithiol itself might be capable of directly detoxifying electrophilic molecules. GENERAL SIGNIFICANCE BstA is an active bacillithiol transferase from S. aureus Newman and is the first DinB/YfiT-like Superfamily member identified from this organism. Interestingly, BstA is highly divergent from B. subtilis YfiT.
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Affiliation(s)
- Varahenage R Perera
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377
| | - Gerald L Newton
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377
| | - Jonathan M Parnell
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0378
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0378
| | - Kit Pogliano
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0377.
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13
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Hernick M. Mycothiol: a target for potentiation of rifampin and other antibiotics againstMycobacterium tuberculosis. Expert Rev Anti Infect Ther 2014; 11:49-67. [DOI: 10.1586/eri.12.152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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14
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Novel L-cysteine-dependent maleylpyruvate isomerase in the gentisate pathway of Paenibacillus sp. strain NyZ101. J Bacteriol 2012; 194:3987-94. [PMID: 22636771 DOI: 10.1128/jb.00050-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Glutathione- and mycothiol-dependent maleylpyruvate isomerases are known to be involved, respectively, in gentisate catabolism in Gram-negative and high G+C Gram-positive strains. In the present study, a low-G+C Gram-positive Paenibacillus sp. strain, NyZ101, was isolated and shown to degrade 3-hydroxybenzoate via gentisate. A 6.5-kb fragment containing a conserved region of gentisate 1,2-dioxygenase genes was cloned and sequenced, and four genes (bagKLIX) were shown to encode the enzymes involved in the catabolism to central metabolites of 3-hydroxybenzoate via gentisate. The Bag proteins share moderate identities with the reported enzymes in the 3-hydroxybenzoate catabolism, except BagL that had no obvious homology with any functionally characterized proteins. Recombinant BagL was purified to homogeneity as a His-tagged protein and likely a dimer by gel filtration. BagL was demonstrated to be a novel thiol-dependent maleylpyruvate isomerase catalyzing the isomerization of maleylpyruvate to fumarylpyruvate with L-cysteine, cysteinylglycine, or glutathione, as its cofactor. The K(m) values of these three thiols for BagL were 15.5, 8.4, and 552 μM, respectively. Since cysteine and coenzyme A were reported to be abundant in low-G+C Gram-positive strains, BagL should utilize L-cysteine as its physiological cofactor in vivo. The addition of Ni(2+) increased BagL activity, and site-directed mutagenesis experiments indicated that three conserved histidines in BagL were associated with binding to Ni(2+) ion and were necessary for its enzyme activity. BagL is the first characterized L-cysteine-dependent catabolic enzyme in microbial metabolism and is likely a new and distinct member of DinB family, with a four-helix-bundle topology, as deduced by sequence analysis and homology modeling.
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15
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Newton GL, Leung SS, Wakabayashi JI, Rawat M, Fahey RC. The DinB superfamily includes novel mycothiol, bacillithiol, and glutathione S-transferases. Biochemistry 2011; 50:10751-60. [PMID: 22059487 DOI: 10.1021/bi201460j] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The superfamily of glutathione S-transferases has been the subject of extensive study; however, Actinobacteria produce mycothiol (MSH) in place of glutathione, and no mycothiol S-transferase (MST) has been identified. Using mycothiol and monochlorobimane as substrates, an MST activity was detected in extracts of Mycobacterium smegmatis and purified sufficiently to allow identification of MSMEG_0887, a member the DUF664 family of the DinB superfamily, as the MST. The identity of the M. smegmatis and homologous Mycobacterium tuberculosis (Rv0443) enzymes was confirmed by cloning, and the expressed proteins were found to be active with MSH but not bacillithiol (BSH) or glutathione (GSH). Bacillus subtilis YfiT is another member of the DinB superfamily, but this bacterium produces BSH. The YfiT protein was shown to have S-transferase activity with monochlorobimane when assayed with BSH but not with MSH or GSH. Enterococcus faecalis EF_3021 shares some homology with MSMEG_0887, but En. faecalis produces GSH but not MSH or BSH. Cloned and expressed EF_0321 was active with monochlorobimane and GSH but not with MSH or BSH. MDMPI_2 is another member of the DinB superfamily and has been previously shown to have mycothiol-dependent maleylpyruvate isomerase activity. Three of the eight families of the DinB superfamily include proteins shown to catalyze thiol-dependent metabolic or detoxification activities. Because more than two-thirds of the sequences assigned to the DinB superfamily are members of these families, it seems likely that such activity is dominant in the DinB superfamily.
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Affiliation(s)
- Gerald L Newton
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093, United States
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