1
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Shen Z, Zhang CY, Gull T, Zhang S. Comparison of genotypic and phenotypic antimicrobial resistance profiles of Salmonella enterica isolates from poultry diagnostic specimens. J Vet Diagn Invest 2024; 36:529-537. [PMID: 38571400 PMCID: PMC11185115 DOI: 10.1177/10406387241242118] [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: 04/05/2024] Open
Abstract
The spread of antimicrobial-resistant bacteria is a significant concern, as it can lead to increased morbidity and mortality in both humans and animals. Whole-genome sequencing (WGS) is a powerful tool that can be used to conduct a comprehensive analysis of the genetic basis of antimicrobial resistance (AMR). We compared the phenotypic and genotypic AMR profiles of 97 Salmonella isolates derived from chicken and turkey diagnostic samples. We focused AMR analysis on 5 antimicrobial classes: aminoglycoside, beta-lactam, phenicol, tetracycline, and trimethoprim. The overall sensitivity and specificity of WGS in predicting phenotypic antimicrobial resistance in the Salmonella isolates were 93.4% and 99.8%, respectively. There were 16 disagreement instances, including 15 that were phenotypically resistant but genotypically susceptible; the other instance involved phenotypic susceptibility but genotypic resistance. Of the isolates examined, 67 of 97 (69%) carried at least 1 resistance gene, with 1 isolate carrying as many as 12 resistance genes. Of the 31 AMR genes analyzed, 16 were identified as aminoglycoside-resistance genes, followed by 4 beta-lactam-resistance, 3 tetracycline-resistance, 2 sulfonamide-resistance, and 1 each of fosfomycin-, quinolone-, phenicol-, trimethoprim-, bleomycin-, and colistin-resistance genes. Most of the resistance genes found were located on plasmids.
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Affiliation(s)
- Zhenyu Shen
- Veterinary Medical Diagnostic Laboratory and Department of Veterinary Pathobiology, College Veterinary Medicine, University of Missouri–Columbia, Columbia, MO, USA
| | - C. Y. Zhang
- Veterinary Medical Diagnostic Laboratory and Department of Veterinary Pathobiology, College Veterinary Medicine, University of Missouri–Columbia, Columbia, MO, USA
| | - Tamara Gull
- Veterinary Medical Diagnostic Laboratory and Department of Veterinary Pathobiology, College Veterinary Medicine, University of Missouri–Columbia, Columbia, MO, USA
| | - Shuping Zhang
- Veterinary Medical Diagnostic Laboratory and Department of Veterinary Pathobiology, College Veterinary Medicine, University of Missouri–Columbia, Columbia, MO, USA
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2
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Gutiérrez-Fernández J, Hersleth HP, Hammerstad M. The crystal structure of mycothiol disulfide reductase (Mtr) provides mechanistic insight into the specific low-molecular-weight thiol reductase activity of Actinobacteria. Acta Crystallogr D Struct Biol 2024; 80:181-193. [PMID: 38372589 PMCID: PMC10910545 DOI: 10.1107/s205979832400113x] [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: 10/21/2023] [Accepted: 02/01/2024] [Indexed: 02/20/2024] Open
Abstract
Low-molecular-weight (LMW) thiols are involved in many processes in all organisms, playing a protective role against reactive species, heavy metals, toxins and antibiotics. Actinobacteria, such as Mycobacterium tuberculosis, use the LMW thiol mycothiol (MSH) to buffer the intracellular redox environment. The NADPH-dependent FAD-containing oxidoreductase mycothiol disulfide reductase (Mtr) is known to reduce oxidized mycothiol disulfide (MSSM) to MSH, which is crucial to maintain the cellular redox balance. In this work, the first crystal structures of Mtr are presented, expanding the structural knowledge and understanding of LMW thiol reductases. The structural analyses and docking calculations provide insight into the nature of Mtrs, with regard to the binding and reduction of the MSSM substrate, in the context of related oxidoreductases. The putative binding site for MSSM suggests a similar binding to that described for the homologous glutathione reductase and its respective substrate glutathione disulfide, but with distinct structural differences shaped to fit the bulkier MSSM substrate, assigning Mtrs as uniquely functioning reductases. As MSH has been acknowledged as an attractive antitubercular target, the structural findings presented in this work may contribute towards future antituberculosis drug development.
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Affiliation(s)
- Javier Gutiérrez-Fernández
- Section for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo, 0318 Oslo, Norway
| | - Hans-Petter Hersleth
- Section for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
| | - Marta Hammerstad
- Section for Biochemistry and Molecular Biology, Department of Biosciences, University of Oslo, PO Box 1066, Blindern, 0316 Oslo, Norway
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3
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Negrellos A, Rice AM, Dos Santos PC, King SB. Sulfinamide Formation from the Reaction of Bacillithiol and Nitroxyl. ACS Chem Biol 2023; 18:2524-2534. [PMID: 38012810 PMCID: PMC11229778 DOI: 10.1021/acschembio.3c00526] [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: 11/29/2023]
Abstract
Bacillithiol (BSH) replaces glutathione (GSH) as the most prominent low-molecular-weight thiol in many low G + C gram-positive bacteria. BSH plays roles in metal binding, protein/enzyme regulation, detoxification, redox buffering, and bacterial virulence. Given the small amounts of BSH isolated from natural sources and relatively lengthy chemical syntheses, the reactions of BSH with pertinent reactive oxygen, nitrogen, and sulfur species remain largely unexplored. We prepared BSH and exposed it to nitroxyl (HNO), a reactive nitrogen species that influences bacterial sulfur metabolism. The profile of this reaction was distinct from HNO oxidation of GSH, which yielded mixtures of disulfide and sulfinamide. The reaction of BSH and HNO (generated from Angeli's salt) gives only sulfinamide products, including a newly proposed cyclic sulfinamide. Treatment of a glucosamine-cysteine conjugate, which lacks the malic acid group, with HNO forms disulfide, implicating the malic acid group in sulfinamide formation. This finding supports a mechanism involving the formation of an N-hydroxysulfenamide intermediate that dehydrates to a sulfenium ion that can be trapped by water or internally trapped by an amide nitrogen to give the cyclic sulfinamide. The biological relevance of BSH reactivity toward HNO is provided through in vivo experiments demonstrating that Bacillus subtilis exposed to HNO shows a growth phenotype, and a strain unable to produce BSH shows hypersensitivity toward HNO in minimal medium cultures. Thiol analysis of HNO-exposed cultures shows an overall decrease in reduced BSH levels, which is not accompanied by increased levels of BSSB, supporting a model involving the formation of an oxidized sulfinamide derivative, identified in vivo by high-pressure liquid chromatography/mass spectrometry. Collectively, these findings reveal the unique chemistry and biology of HNO with BSH in bacteria that produce this biothiol.
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Affiliation(s)
- Alberto Negrellos
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27107, United States
| | - Allison M Rice
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27107, United States
| | - Patricia C Dos Santos
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27107, United States
| | - S Bruce King
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina 27107, United States
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4
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Hirakawa H, Takita A, Sato Y, Hiramoto S, Hashimoto Y, Ohshima N, Minamishima YA, Murakami M, Tomita H. Inactivation of ackA and pta Genes Reduces GlpT Expression and Susceptibility to Fosfomycin in Escherichia coli. Microbiol Spectr 2023; 11:e0506922. [PMID: 37199605 PMCID: PMC10269713 DOI: 10.1128/spectrum.05069-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 04/29/2023] [Indexed: 05/19/2023] Open
Abstract
Fosfomycin is used to treat a variety of bacterial infections, including urinary tract infections caused by Escherichia coli. In recent years, quinolone-resistant and extended-spectrum β-lactamase (ESBL)-producing bacteria have been increasing. Because fosfomycin is effective against many of these drug-resistant bacteria, the clinical importance of fosfomycin is increasing. Against this background, information on the mechanisms of resistance and the antimicrobial activity of this drug is desired to enhance the usefulness of fosfomycin therapy. In this study, we aimed to explore novel factors affecting the antimicrobial activity of fosfomycin. Here, we found that ackA and pta contribute to fosfomycin activity against E. coli. ackA and pta mutant E. coli had reduced fosfomycin uptake capacity and became less sensitive to this drug. In addition, ackA and pta mutants had decreased expression of glpT that encodes one of the fosfomycin transporters. Expression of glpT is enhanced by a nucleoid-associated protein, Fis. We found that mutations in ackA and pta also caused a decrease in fis expression. Thus, we interpret the decrease in glpT expression in ackA and pta defective strains to be due to a decrease in Fis levels in these mutants. Furthermore, ackA and pta are conserved in multidrug-resistant E. coli isolated from patients with pyelonephritis and enterohemorrhagic E. coli, and deletion of ackA and pta from these strains resulted in decreased susceptibility to fosfomycin. These results suggest that ackA and pta in E. coli contribute to fosfomycin activity and that mutation of these genes may pose a risk of reducing the effect of fosfomycin. IMPORTANCE The spread of drug-resistant bacteria is a major threat in the field of medicine. Although fosfomycin is an old type of antimicrobial agent, it has recently come back into the limelight because of its effectiveness against many drug-resistant bacteria, including quinolone-resistant and ESBL-producing bacteria. Since fosfomycin is taken up into the bacteria by GlpT and UhpT transporters, its antimicrobial activity fluctuates with changes in GlpT and UhpT function and expression. In this study, we found that inactivation of the ackA and pta genes responsible for the acetic acid metabolism system reduced GlpT expression and fosfomycin activity. In other words, this study shows a new genetic mutation that leads to fosfomycin resistance in bacteria. The results of this study will lead to further understanding of the mechanism of fosfomycin resistance and the creation of new ideas to enhance fosfomycin therapy.
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Affiliation(s)
- Hidetada Hirakawa
- Department of Bacteriology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Ayako Takita
- Department of Bacteriology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Yumika Sato
- Department of Bacteriology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Suguru Hiramoto
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Yusuke Hashimoto
- Department of Bacteriology, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Noriyasu Ohshima
- Department of Biochemistry, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Yoji A. Minamishima
- Department of Biochemistry, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Masami Murakami
- Department of Clinical Laboratory Medicine, Gunma University Graduate School of Medicine, Gunma, Japan
| | - Haruyoshi Tomita
- Department of Bacteriology, Gunma University Graduate School of Medicine, Gunma, Japan
- Laboratory of Bacterial Drug Resistance, Gunma University Graduate School of Medicine, Gunma, Japan
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5
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Liu F, Huang H, Sun L, Yan Z, Tan X, Li J, Luo X, Ding H, Xiao Q. P(v) intermediate-mediated E1cB elimination for the synthesis of glycals. Chem Sci 2022; 13:5588-5596. [PMID: 35694351 PMCID: PMC9116453 DOI: 10.1039/d2sc01423h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 04/22/2022] [Indexed: 12/23/2022] Open
Abstract
Glycals are highly versatile and useful building blocks in the chemistry of carbohydrate and natural products. However, the practical synthesis of glycals remains a long-standing and mostly unsolved problem in synthetic chemistry. Herein, we present an unprecedented approach to make a variety of glycals using phosphonium hydrolysis-induced, P(v) intermediate-mediated E1cB elimination. The method provides a highly efficient, practical and scalable strategy for the synthesis of glycals with good generality and excellent yields. Furthermore, the strategy was successfully applied to late-stage modification of complex drug-like molecules. Additionally, the corresponding 1-deuterium-glycals were produced easily by simple tBuONa/D2O-hydrolysis–elimination. Mechanistic investigations indicated that the oxaphosphorane intermediate-mediated E1cB mechanism is responsible for the elimination reaction. A novel glucosylphosphonium-hydrolysis induced E1cB-elimination provides a highly efficient, practical and scalable method for the synthesis of glycals with good compatibility and excellent yields.![]()
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Affiliation(s)
- Fen Liu
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Haiyang Huang
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Longgen Sun
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Zeen Yan
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Xiao Tan
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Jing Li
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Xinyue Luo
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Haixin Ding
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
| | - Qiang Xiao
- Key Laboratory of Organic Chemistry, Institute of Organic Chemistry, Jiangxi Science & Technology Normal University Nanchang 330013 Jiangxi Province China
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6
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Rice AM, Faig A, Wolff DE, King SB. Sodium borohydride and thiol mediated nitrite release from nitroaromatic antibiotics. Bioorg Med Chem Lett 2021; 48:128245. [PMID: 34242759 DOI: 10.1016/j.bmcl.2021.128245] [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] [Received: 05/21/2021] [Revised: 06/24/2021] [Accepted: 06/30/2021] [Indexed: 01/08/2023]
Abstract
Nitroaromatic antibiotics are used to treat a variety of bacterial and parasitic infections. These prodrugs require reductive bioactivation for activity, which provides a pathway for the release of nitrogen oxide species such as nitric oxide, nitrite, and/or nitroxyl. Using sodium borohydride and 2-aminoethanol as model reductants, this work examines release of nitrogen oxide species from various nitroaromatic compounds through several characterization methods. Specifically, 4- and 5-nitroimidazoles reproducibly generate higher amounts of nitrite (not nitric oxide or nitroxyl) than 2-nitroimidazoles during the reaction of model hydride donors or thiols. Mass spectrometric analysis shows clean formation of products resulting from nucleophile addition and nitro group loss. 2-Nitrofurans generate nitrite upon addition of sodium borohydride or 2-aminoethanethiol, but these complex reactions do not produce clean organic products. A mechanism that includes nucleophile addition to the carbon βto the nitro group to generate a nitronate anion followed by protonation and nitrous acid elimination explains the observed products and labeling studies. These systematic studies give a better understanding of the release mechanisms of nitrogen oxide species from these compounds allowing for the design of more efficient therapeutics.
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Affiliation(s)
- Allison M Rice
- Wake Forest University, Department of Chemistry, Winston-Salem, NC 27101, United States of America
| | - Allison Faig
- Wake Forest University, Department of Chemistry, Winston-Salem, NC 27101, United States of America
| | - David E Wolff
- Wake Forest University, Department of Chemistry, Winston-Salem, NC 27101, United States of America
| | - S Bruce King
- Wake Forest University, Department of Chemistry, Winston-Salem, NC 27101, United States of America.
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7
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Hammerstad M, Gudim I, Hersleth HP. The Crystal Structures of Bacillithiol Disulfide Reductase Bdr (YpdA) Provide Structural and Functional Insight into a New Type of FAD-Containing NADPH-Dependent Oxidoreductase. Biochemistry 2020; 59:4793-4798. [PMID: 33326741 PMCID: PMC7774306 DOI: 10.1021/acs.biochem.0c00745] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Low
G+C Gram-positive Firmicutes, such as the clinically important
pathogens Staphylococcus aureus and Bacillus
cereus, use the low-molecular weight thiol bacillithiol (BSH)
as a defense mechanism to buffer the intracellular redox environment
and counteract oxidative stress encountered by human neutrophils during
infections. The protein YpdA has recently been shown to function as
an essential NADPH-dependent reductase of oxidized bacillithiol disulfide
(BSSB) resulting from stress responses and is crucial for maintaining
the reduced pool of BSH and cellular redox balance. In this work,
we present the first crystallographic structures of YpdAs, namely,
those from S. aureus and B. cereus. Our analyses reveal a uniquely organized biological tetramer; however,
the structure of the monomeric subunit is highly similar to those
of other flavoprotein disulfide reductases. The absence of a redox
active cysteine in the vicinity of the FAD isoalloxazine ring implies
a new direct disulfide reduction mechanism, which is backed by the
presence of a potentially gated channel, serving as a putative binding
site for BSSB in the proximity of the FAD cofactor. We also report
enzymatic activities for both YpdAs, which along with the structures
presented in this work provide important structural and functional
insight into a new class of FAD-containing NADPH-dependent oxidoreductases,
related to the emerging fight against pathogenic bacteria.
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Affiliation(s)
- Marta Hammerstad
- Department of Biosciences, University of Oslo, Section for Biochemistry and Molecular Biology, P.O. Box 1066, Blindern, NO-0316 Oslo, Norway
| | - Ingvild Gudim
- Department of Biosciences, University of Oslo, Section for Biochemistry and Molecular Biology, P.O. Box 1066, Blindern, NO-0316 Oslo, Norway
| | - Hans-Petter Hersleth
- Department of Biosciences, University of Oslo, Section for Biochemistry and Molecular Biology, P.O. Box 1066, Blindern, NO-0316 Oslo, Norway.,Department of Chemistry, University of Oslo, Section for Chemical Life Sciences, P.O. Box 1033, Blindern, NO-0315 Oslo, Norway
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8
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Rawat M, Maupin-Furlow JA. Redox and Thiols in Archaea. Antioxidants (Basel) 2020; 9:antiox9050381. [PMID: 32380716 PMCID: PMC7278568 DOI: 10.3390/antiox9050381] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 12/11/2022] Open
Abstract
Low molecular weight (LMW) thiols have many functions in bacteria and eukarya, ranging from redox homeostasis to acting as cofactors in numerous reactions, including detoxification of xenobiotic compounds. The LMW thiol, glutathione (GSH), is found in eukaryotes and many species of bacteria. Analogues of GSH include the structurally different LMW thiols: bacillithiol, mycothiol, ergothioneine, and coenzyme A. Many advances have been made in understanding the diverse and multiple functions of GSH and GSH analogues in bacteria but much less is known about distribution and functions of GSH and its analogues in archaea, which constitute the third domain of life, occupying many niches, including those in extreme environments. Archaea are able to use many energy sources and have many unique metabolic reactions and as a result are major contributors to geochemical cycles. As LMW thiols are major players in cells, this review explores the distribution of thiols and their biochemistry in archaea.
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Affiliation(s)
- Mamta Rawat
- Biology Department, California State University, Fresno, CA 93740, USA
- Correspondence: (M.R.); (J.A.M.-F.)
| | - Julie A. Maupin-Furlow
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611, USA
- Genetics Institute, University of Florida, Gainesville, FL 32611, USA
- Correspondence: (M.R.); (J.A.M.-F.)
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9
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Ahadi S, Awan SI, Werz DB. Total Synthesis of Tri-, Hexa- and Heptasaccharidic Substructures of the O-Polysaccharide of Providencia rustigianii O34. Chemistry 2020; 26:6264-6270. [PMID: 32092205 PMCID: PMC7318715 DOI: 10.1002/chem.202000496] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/20/2020] [Indexed: 12/22/2022]
Abstract
A general and efficient strategy for synthesis of tri‐, hexa‐ and heptasaccharidic substructures of the lipopolysaccharide of Providencia rustigianii O34 is described. For the heptasaccharide seven different building blocks were employed. Special features of the structures are an α‐linked galactosamine and the two embedded α‐fucose units, which are either branched at positions‐3 and ‐4 or further linked at their 2‐position. Convergent strategies focused on [4+3], [3+4], and [4+2+1] couplings. Whereas the [4+3] and [3+4] coupling strategies failed the [4+2+1] strategy was successful. As monosaccharidic building blocks trichloroacetimidates and phosphates were employed. Global deprotection of the fully protected structures was achieved by Birch reaction.
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Affiliation(s)
- Somayeh Ahadi
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106, Braunschweig, Germany
| | - Shahid I Awan
- Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Tammannstraße 2, 37077, Göttingen, Germany
| | - Daniel B Werz
- Technische Universität Braunschweig, Institute of Organic Chemistry, Hagenring 30, 38106, Braunschweig, Germany
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10
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Woodward RL, Castleman MM, Meloche CE, Karpen ME, Carlson CG, Yobi WH, Jepsen JC, Lewis BW, Zarnosky BN, Cook PD. X-ray crystallographic structure of BshB, the zinc-dependent deacetylase involved in bacillithiol biosynthesis. Protein Sci 2019; 29:1035-1039. [PMID: 31867856 DOI: 10.1002/pro.3808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 11/05/2022]
Abstract
Many gram-positive bacteria produce bacillithiol to aid in the maintenance of redox homeostasis and degradation of toxic compounds, including the antibiotic fosfomycin. Bacillithiol is produced via a three-enzyme pathway that includes the action of the zinc-dependent deacetylase BshB. Previous studies identified conserved aspartate and histidine residues within the active site that are involved in metal binding and catalysis, but the enzymatic mechanism is not fully understood. Here we report two X-ray crystallographic structures of BshB from Bacillus subtilis that provide insight into the BshB catalytic mechanism.
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Affiliation(s)
- Robert L Woodward
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, Ohio
| | | | - Chelsea E Meloche
- Department of Chemistry, Grand Valley State University, Allendale, Michigan
| | - Mary E Karpen
- Department of Chemistry, Grand Valley State University, Allendale, Michigan
| | - Clare G Carlson
- Department of Chemistry, Grand Valley State University, Allendale, Michigan
| | - William H Yobi
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, Ohio
| | - Jacqueline C Jepsen
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, Ohio
| | - Benjamin W Lewis
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, Ohio
| | - Brooke N Zarnosky
- Department of Chemistry and Biochemistry, University of Mount Union, Alliance, Ohio
| | - Paul D Cook
- Department of Chemistry, Grand Valley State University, Allendale, Michigan
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11
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Antimicrobial garlic-derived diallyl polysulfanes: Interactions with biological thiols in Bacillus subtilis. Biochim Biophys Acta Gen Subj 2019; 1863:1050-1058. [DOI: 10.1016/j.bbagen.2019.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 03/08/2019] [Accepted: 03/14/2019] [Indexed: 12/18/2022]
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12
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Royer CJ, Cook PD. A structural and functional analysis of the glycosyltransferase BshA from Staphylococcus aureus: Insights into the reaction mechanism and regulation of bacillithiol production. Protein Sci 2019; 28:1083-1094. [PMID: 30968475 DOI: 10.1002/pro.3617] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/05/2019] [Accepted: 04/08/2019] [Indexed: 01/20/2023]
Abstract
Bacillithiol is a glucosamine-derived antioxidant found in several pathogenic Gram-positive bacteria. The compound is involved in maintaining the appropriate redox state within the cell as well as detoxifying foreign agents like the antibiotic fosfomycin. Bacillithiol is produced via the action of three enzymes, including BshA, a retaining GT-B glycosyltransferase that utilizes UDP-N-acetylglucosamine and l-malate to produce N-acetylglucosaminyl-malate. Recent studies suggest that retaining GT-B glycosyltransferases like BshA utilize a substrate-assisted mechanism that goes through an SN i-like transition state. In a previous study, we relied on X-ray crystallography as well as computational simulations to hypothesize the manner in which substrates would bind the enzyme, but several questions about substrate binding and the role of one of the amino acid residues persisted. Another study demonstrated that BshA might be subject to feedback inhibition by bacillithiol, but this phenomenon was not analyzed further to determine the exact mechanism of inhibition. Here we present X-ray crystallographic structures and steady-state kinetics results that help elucidate both of these issues. Our ligand-bound crystal structures demonstrate that the active site provides an appropriate steric and geometric arrangement of ligands to facilitate the substrate-assisted mechanism. Finally, we show that bacillithiol is competitive for UDP-N-acetylglucosamine with a Ki value near 120-130 μM and likely binds within the BshA active site, suggesting that bacillithiol modulates BshA activity via feedback inhibition. The work presented here furthers our understanding of bacillithiol metabolism and can aid in the development of inhibitors to counteract resistance to antibiotics such as fosfomycin.
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Affiliation(s)
| | - Paul D Cook
- Department of Chemistry, Grand Valley State University, Allendale, Michigan
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13
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Physiological Studies of Chlorobiaceae Suggest that Bacillithiol Derivatives Are the Most Widespread Thiols in Bacteria. mBio 2018; 9:mBio.01603-18. [PMID: 30482829 PMCID: PMC6282198 DOI: 10.1128/mbio.01603-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Low-molecular-weight thiols are key metabolites that participate in many basic cellular processes: central metabolism, detoxification, and oxidative stress resistance. Here we describe a new thiol, N-methyl-bacillithiol, found in an anaerobic phototrophic bacterium and identify a gene that is responsible for its synthesis from bacillithiol, the main thiol metabolite in many Gram-positive bacteria. We show that the presence or absence of this gene in a sequenced genome accurately predicts thiol content in distantly related bacteria. On the basis of these results, we analyzed genome data and predict that bacillithiol and its derivatives are the most widely distributed thiol metabolites in biology. Low-molecular-weight (LMW) thiols mediate redox homeostasis and the detoxification of chemical stressors. Despite their essential functions, the distribution of LMW thiols across cellular life has not yet been defined. LMW thiols are also thought to play a central role in sulfur oxidation pathways in phototrophic bacteria, including the Chlorobiaceae. Here we show that Chlorobaculum tepidum synthesizes a novel LMW thiol with a mass of 412 ± 1 Da corresponding to a molecular formula of C14H24N2O10S, which suggests that the new LMW thiol is closely related to bacillithiol (BSH), the major LMW thiol of low-G+C Gram-positive bacteria. The Cba. tepidum LMW thiol structure was N-methyl-bacillithiol (N-Me-BSH), methylated on the cysteine nitrogen, the fourth instance of this modification in metabolism. Orthologs of bacillithiol biosynthetic genes in the Cba. tepidum genome and the CT1040 gene product, N-Me-BSH synthase, were required for N-Me-BSH synthesis. N-Me-BSH was found in all Chlorobiaceae examined as well as Polaribacter sp. strain MED152, a member of the Bacteroidetes. A comparative genomic analysis indicated that BSH/N-Me-BSH is synthesized not only by members of the Chlorobiaceae, Bacteroidetes, Deinococcus-Thermus, and Firmicutes but also by Acidobacteria, Chlamydiae, Gemmatimonadetes, and Proteobacteria. Thus, BSH and derivatives appear to be the most broadly distributed LMW thiols in biology.
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Mass spectrometric studies of Cu(I)-binding to the N-terminal domains of B. subtilis CopA and influence of bacillithiol. J Inorg Biochem 2018; 190:24-30. [PMID: 30342352 DOI: 10.1016/j.jinorgbio.2018.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/11/2018] [Accepted: 10/12/2018] [Indexed: 11/20/2022]
Abstract
CopA is a Cu(I)-exporting transmembrane P1B-type ATPase from Bacillus subtilis. It contains two N-terminal cytoplasmic domains, CopAab, which bind Cu(I) with high affinity and to form higher-order complexes with multiple Cu(I) ions. To determine the precise nature of these species, electrospray ionisation mass spectrometry (ESI-MS) under non-denaturing conditions was employed. Up to 1 Cu per CopAab resulted in Cu coordination to one or both CopAab domains. At >1 Cu/CopAab, two distinct dimeric charge state envelopes were observed, corresponding to distinct conformations, each with Cu6(CopAab)2 as its major form. The influence of the physiologically relevant low molecular weight thiol bacillithiol (BSH) on Cu(I)-binding to CopAab was assessed. Dimeric CopAab persisted in the presence of BSH, with previously undetected Cu7(CopAab)2 and Cu6(CopAab)2(BSH) forms apparent.
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15
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Zhanel GG, Zhanel MA, Karlowsky JA. Intravenous Fosfomycin: An Assessment of Its Potential for Use in the Treatment of Systemic Infections in Canada. THE CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY = JOURNAL CANADIEN DES MALADIES INFECTIEUSES ET DE LA MICROBIOLOGIE MEDICALE 2018; 2018:8912039. [PMID: 30046362 PMCID: PMC6036856 DOI: 10.1155/2018/8912039] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 11/17/2022]
Abstract
Fosfomycin is a bactericidal agent that inhibits cell wall synthesis using a mechanism of action distinct from β-lactams or other antimicrobial agents. It is a broad-spectrum agent that is frequently active against antimicrobial-resistant bacterial pathogens including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), multidrug-resistant (MDR) Enterobacteriaceae, and some isolates of MDR Pseudomonas aeruginosa. Intravenous fosfomycin has been prescribed for a wide variety of infections in many countries for >40 years. It is most frequently used in combination with other antimicrobial agents (e.g., β-lactams, carbapenems, and aminoglycosides) and has an excellent safety profile, including in neonates and children, even with long-term administration (weeks). Fosfomycin achieves extensive tissue distribution including difficult to reach compartments such as aqueous humor, vitreous humor, abscess fluid, and CSF. Available data, to date, suggest no clinically relevant pharmacological interactions between fosfomycin and other agents, including drugs, stimulants, or food. Intravenous fosfomycin's role in therapy in Canada is likely as an agent used alone or in combination for complicated urinary tract infections in hospitalized patients as well as hospitalized patients with MDR infections who have not responded to first-, and potentially, second-line antimicrobials or in patients who cannot tolerate (due to adverse effects) first- and second-line antimicrobials.
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Affiliation(s)
- George G. Zhanel
- Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - Michael A. Zhanel
- Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | - James A. Karlowsky
- Department of Medical Microbiology and Infectious Diseases, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
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16
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Abstract
SIGNIFICANCE Since the discovery and structural characterization of bacillithiol (BSH), the biochemical functions of BSH-biosynthesis enzymes (BshA/B/C) and BSH-dependent detoxification enzymes (FosB, Bst, GlxA/B) have been explored in Bacillus and Staphylococcus species. It was shown that BSH plays an important role in detoxification of reactive oxygen and electrophilic species, alkylating agents, toxins, and antibiotics. Recent Advances: More recently, new functions of BSH were discovered in metal homeostasis (Zn buffering, Fe-sulfur cluster, and copper homeostasis) and virulence control in Staphylococcus aureus. Unexpectedly, strains of the S. aureus NCTC8325 lineage were identified as natural BSH-deficient mutants. Modern mass spectrometry-based approaches have revealed the global reach of protein S-bacillithiolation in Firmicutes as an important regulatory redox modification under hypochlorite stress. S-bacillithiolation of OhrR, MetE, and glyceraldehyde-3-phosphate dehydrogenase (Gap) functions, analogous to S-glutathionylation, as both a redox-regulatory device and in thiol protection under oxidative stress. CRITICAL ISSUES Although the functions of the bacilliredoxin (Brx) pathways in the reversal of S-bacillithiolations have been recently addressed, significantly more work is needed to establish the complete Brx reduction pathway, including the major enzyme(s), for reduction of oxidized BSH (BSSB) and the targets of Brx action in vivo. FUTURE DIRECTIONS Despite the large number of identified S-bacillithiolated proteins, the physiological relevance of this redox modification was shown for only selected targets and should be a subject of future studies. In addition, many more BSH-dependent detoxification enzymes are evident from previous studies, although their roles and biochemical mechanisms require further study. This review of BSH research also pin-points these missing gaps for future research. Antioxid. Redox Signal. 28, 445-462.
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Affiliation(s)
- Pete Chandrangsu
- 1 Department of Microbiology, Cornell University , Ithaca, New York
| | - Vu Van Loi
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - Haike Antelmann
- 2 Institute for Biology-Microbiology , Freie Universität Berlin, Berlin, Germany
| | - John D Helmann
- 1 Department of Microbiology, Cornell University , Ithaca, New York
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17
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Chandrangsu P, Rensing C, Helmann JD. Metal homeostasis and resistance in bacteria. Nat Rev Microbiol 2017; 15:338-350. [PMID: 28344348 DOI: 10.1038/nrmicro.2017.15] [Citation(s) in RCA: 403] [Impact Index Per Article: 57.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metal ions are essential for many reactions, but excess metals can be toxic. In bacteria, metal limitation activates pathways that are involved in the import and mobilization of metals, whereas excess metals induce efflux and storage. In this Review, we highlight recent insights into metal homeostasis, including protein-based and RNA-based sensors that interact directly with metals or metal-containing cofactors. The resulting transcriptional response to metal stress takes place in a stepwise manner and is reinforced by post-transcriptional regulatory systems. Metal limitation and intoxication by the host are evolutionarily ancient strategies for limiting bacterial growth. The details of the resulting growth restriction are beginning to be understood and seem to be organism-specific.
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Affiliation(s)
- Pete Chandrangsu
- Department of Microbiology, Cornell University, Wing Hall, 123 Wing Drive, Ithaca, New York 14853, USA
| | - Christopher Rensing
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China.,Department of Agricultural Resource and Environment, College of Resources and the Environment, Fujian Agriculture &Forestry University, Boxbue Building, 15 Shangxiadian Road, Cangshan District, Fuzhou, Fujian 350002, China.,J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, California 92037, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Wing Hall, 123 Wing Drive, Ithaca, New York 14853, USA
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18
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Winchell KR, Egeler PW, VanDuinen AJ, Jackson LB, Karpen ME, Cook PD. A Structural, Functional, and Computational Analysis of BshA, the First Enzyme in the Bacillithiol Biosynthesis Pathway. Biochemistry 2016; 55:4654-65. [PMID: 27454321 PMCID: PMC5954418 DOI: 10.1021/acs.biochem.6b00472] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Bacillithiol is a compound produced by several Gram-positive bacterial species, including the human pathogens Staphylococcus aureus and Bacillus anthracis. It is involved in maintaining cellular redox balance as well as the destruction of reactive oxygen species and harmful xenobiotic agents, including the antibiotic fosfomycin. BshA, BshB, and BshC are the enzymes involved in bacillithiol biosynthesis. BshA is a retaining glycosyltransferase responsible for the first committed step in bacillithiol production, namely the addition of N-acetylglucosamine to l-malate. Retaining glycosyltransferases like BshA are proposed to utilize an SNi-like reaction mechanism in which leaving group departure and nucleophilic attack occur on the same face of the hexose. However, significant questions regarding the details of how BshA and similar enzymes accommodate their substrates and facilitate catalysis persist. Here we report X-ray crystallographic structures of BshA from Bacillus subtilis 168 bound with UMP and/or GlcNAc-mal at resolutions of 2.15 and 2.02 Å, respectively. These ligand-bound structures, along with our functional and computational studies, provide clearer insight into how BshA and other retaining GT-B glycosyltransferases operate, corroborating the substrate-assisted, SNi-like reaction mechanism. The analyses presented herein can serve as the basis for the design of inhibitors capable of preventing bacillithiol production and, subsequently, help combat resistance to fosfomycin in various pathogenic Gram-positive microorganisms.
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Affiliation(s)
- Kelsey R. Winchell
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401, United States
| | - Paul W. Egeler
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401, United States
| | - Andrew J. VanDuinen
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, Michigan, 49401, United States
| | - Luke B. Jackson
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401, United States
| | - Mary E. Karpen
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401, United States
| | - Paul D. Cook
- Department of Chemistry, Grand Valley State University, Allendale, Michigan, 49401, United States
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, Michigan, 49401, United States
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Fosfomycin: A First-Line Oral Therapy for Acute Uncomplicated Cystitis. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2016; 2016:2082693. [PMID: 27366158 PMCID: PMC4904571 DOI: 10.1155/2016/2082693] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 03/31/2016] [Indexed: 11/20/2022]
Abstract
Fosfomycin is a new agent to Canada approved for the treatment of acute uncomplicated cystitis (AUC) in adult women infected with susceptible isolates of E. coli and Enterococcus faecalis. We reviewed the literature regarding the use of oral fosfomycin for the treatment of AUC. All English-language references from 1975 to October 2015 were reviewed. In Canada, fosfomycin tromethamine is manufactured as Monurol® and is available as a 3-gram single dose sachet. Fosfomycin has a unique chemical structure, inhibiting peptidoglycan synthesis at an earlier site compared to β-lactams with no cross-resistance with other agents. Fosfomycin displays broad-spectrum activity against ESBL-producing, AmpC-producing, carbapenem-non-susceptible, and multidrug-resistant (MDR) E. coli. Resistance to fosfomycin in E. coli is rare (<1%). Fosfomycin is excreted unchanged in the urine by glomerular filtration with peak urinary concentration ~4000 µg/mL and remains at concentrations >100 µg/mL for 48 hours after a single 3-gram oral dose. No dosage adjustments are required in elderly patients, in pregnant patients, or in either renal or hepatic impairment. Fosfomycin demonstrates a favorable safety profile, and clinical trials have demonstrated efficacy in AUC that is comparable to ciprofloxacin, nitrofurantoin, and trimethoprim-sulfamethoxazole. Fosfomycin's in vitro activity against common uropathogens, including MDR isolates, its favorable safety profile including pregnancy patients, drug interactions, and clinical trials data demonstrating efficacy in AUC, has resulted in Canadian, US, and European guidelines/authorities recommending fosfomycin as a first line agent for the treatment of AUC.
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20
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Kay KL, Hamilton CJ, Le Brun NE. Mass spectrometry of B. subtilis CopZ: Cu(i)-binding and interactions with bacillithiol. Metallomics 2016; 8:709-19. [DOI: 10.1039/c6mt00036c] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Mass spectrometry reveals a high resolution overview of species formed by CopZ and Cu(i), and the effects of the physiological low molecular weight thiol bacillithiol.
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Affiliation(s)
- Kristine L. Kay
- Centre for Molecular and Structural Biochemistry
- School of Chemistry
- University of East Anglia
- Norwich, UK
| | | | - Nick E. Le Brun
- Centre for Molecular and Structural Biochemistry
- School of Chemistry
- University of East Anglia
- Norwich, UK
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21
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Fang Z, Dos Santos PC. Protective role of bacillithiol in superoxide stress and Fe-S metabolism in Bacillus subtilis. Microbiologyopen 2015; 4:616-31. [PMID: 25988368 PMCID: PMC4554457 DOI: 10.1002/mbo3.267] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 04/16/2015] [Accepted: 04/17/2015] [Indexed: 01/22/2023] Open
Abstract
Glutathione (GSH) serves as the prime thiol in most organisms as its depletion increases antibiotic and metal toxicity, impairs oxidative stress responses, and affects Fe and Fe–S cluster metabolism. Many gram-positive bacteria lack GSH, but instead produce other structurally unrelated yet functionally equivalent thiols. Among those, bacillithiol (BSH) has been recently identified in several low G+C gram-positive bacteria. In this work, we have explored the link between BSH and Fe–S metabolism in Bacillus subtilis. We have identified that B. subtilis lacking BSH is more sensitive to oxidative stress (paraquat), and metal toxicity (Cu(I) and Cd(II)), but not H2O2. Furthermore, a slow growth phenotype of BSH null strain in minimal medium was observed, which could be recovered upon the addition of selected amino acids (Leu/Ile and Glu/Gln), supplementation of iron, or chemical complementation with BSH disulfide (BSSB) to the growth medium. Interestingly, Fe–S cluster containing isopropylmalate isomerase (LeuCD) and glutamate synthase (GOGAT) showed decreased activities in BSH null strain. Deficiency of BSH also resulted in decreased levels of intracellular Fe accompanied by increased levels of manganese and altered expression levels of Fe–S cluster biosynthetic SUF components. Together, this study is the first to establish a link between BSH and Fe–S metabolism in B. subtilis.
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Affiliation(s)
- Zhong Fang
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, 27016
| | - Patricia C Dos Santos
- Department of Chemistry, Wake Forest University, Winston-Salem, North Carolina, 27016
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22
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VanDuinen AJ, Winchell KR, Keithly ME, Cook PD. X-ray crystallographic structure of BshC, a unique enzyme involved in bacillithiol biosynthesis. Biochemistry 2014; 54:100-3. [PMID: 25496067 PMCID: PMC4303302 DOI: 10.1021/bi501394q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
![]()
Bacillithiol
is produced by many Gram-positive bacteria via a pathway
utilizing the enzymes BshA, BshB, and BshC. Here we report the 1.77
Å resolution crystal structure of BshC, the putative cysteine
ligase in bacillithiol production. The structure reveals that BshC
contains a core Rossmann fold with connecting peptide motifs (CP1
and CP2) and a unique α-helical coiled-coil domain that facilitates
dimerization. The model contains citrate and glycerol in the canonical
active site and ADP in a second binding pocket. The overall structure
and bound ligands give insight into the function of this unique enzyme.
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Affiliation(s)
- Andrew J VanDuinen
- Department of Cell & Molecular Biology, Grand Valley State University , Allendale, Michigan 49401, United States
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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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Gaballa A, Chi BK, Roberts AA, Becher D, Hamilton CJ, Antelmann H, Helmann JD. Redox regulation in Bacillus subtilis: The bacilliredoxins BrxA(YphP) and BrxB(YqiW) function in de-bacillithiolation of S-bacillithiolated OhrR and MetE. Antioxid Redox Signal 2014; 21:357-67. [PMID: 24313874 PMCID: PMC4076974 DOI: 10.1089/ars.2013.5327] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AIMS In bacillithiol (BSH)-utilizing organisms, protein S-bacillithiolation functions as a redox switch in response to oxidative stress and protects critical Cys residues against overoxidation. In Bacillus subtilis, both the redox-sensing repressor OhrR and the methionine synthase MetE are redox controlled by S-bacillithiolation in vivo. Here, we identify pathways of protein de-bacillithiolation and test the hypothesis that YphP(BrxA) and YqiW(BrxB) act as bacilliredoxins (Brx) to remove BSH from OhrR and MetE mixed disulfides. RESULTS We present evidence that the BrxA and BrxB paralogs have de-bacillithiolation activity. This Brx activity results from attack of the amino-terminal Cys residue in a CGC motif on protein BSH-mixed disulfides. B. subtilis OhrR DNA-binding activity is eliminated by S-thiolation on its sole Cys residue. Both the BrxA and BrxB bacilliredoxins mediate de-bacillithiolation of OhrR accompanied by the transfer of BSH to the amino-terminal cysteine of their CGC active site motif. In vitro studies demonstrate that BrxB can restore DNA-binding activity to OhrR which is S-bacillithiolated, but not to OhrR that is S-cysteinylated. MetE is most strongly S-bacillithiolated at Cys719 in vitro and can be efficiently de-bacillithiolated by both BrxA and BrxB. INNOVATION AND CONCLUSION We demonstrate that BrxA and BrxB function in the reduction of BSH mixed protein disulfides with two natural substrates (MetE, OhrR). These results provide biochemical evidence for a new class of bacterial redox-regulatory proteins, the bacilliredoxins, which function analogously to glutaredoxins. Bacilliredoxins function in concert with other thiol-disulfide oxidoreductases to maintain redox homeostasis in response to disulfide stress conditions.
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Affiliation(s)
- Ahmed Gaballa
- 1 Department of Microbiology, Cornell University , Ithaca, New York
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25
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Handtke S, Schroeter R, Jürgen B, Methling K, Schlüter R, Albrecht D, van Hijum SAFT, Bongaerts J, Maurer KH, Lalk M, Schweder T, Hecker M, Voigt B. Bacillus pumilus reveals a remarkably high resistance to hydrogen peroxide provoked oxidative stress. PLoS One 2014; 9:e85625. [PMID: 24465625 PMCID: PMC3896406 DOI: 10.1371/journal.pone.0085625] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 12/05/2013] [Indexed: 12/16/2022] Open
Abstract
Bacillus pumilus is characterized by a higher oxidative stress resistance than other comparable industrially relevant Bacilli such as B. subtilis or B. licheniformis. In this study the response of B. pumilus to oxidative stress was investigated during a treatment with high concentrations of hydrogen peroxide at the proteome, transcriptome and metabolome level. Genes/proteins belonging to regulons, which are known to have important functions in the oxidative stress response of other organisms, were found to be upregulated, such as the Fur, Spx, SOS or CtsR regulon. Strikingly, parts of the fundamental PerR regulon responding to peroxide stress in B. subtilis are not encoded in the B. pumilus genome. Thus, B. pumilus misses the catalase KatA, the DNA-protection protein MrgA or the alkyl hydroperoxide reductase AhpCF. Data of this study suggests that the catalase KatX2 takes over the function of the missing KatA in the oxidative stress response of B. pumilus. The genome-wide expression analysis revealed an induction of bacillithiol (Cys-GlcN-malate, BSH) relevant genes. An analysis of the intracellular metabolites detected high intracellular levels of this protective metabolite, which indicates the importance of bacillithiol in the peroxide stress resistance of B. pumilus.
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Affiliation(s)
- Stefan Handtke
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
| | - Rebecca Schroeter
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Britta Jürgen
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
| | - Karen Methling
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Rabea Schlüter
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
| | - Dirk Albrecht
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
| | - Sacha A. F. T. van Hijum
- Centre for Molecular and Biomolecular Informatics (CMBI), Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; and Division Processing and Safety, NIZO Food Research B.V., Ede, The Netherlands
| | - Johannes Bongaerts
- Department of Chemistry and Biotechnology, Aachen University of Applied Sciences, Jülich, Germany
| | | | - Michael Lalk
- Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Thomas Schweder
- Pharmaceutical Biotechnology, Institute of Pharmacy, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Michael Hecker
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
| | - Birgit Voigt
- Institute for Microbiology, University of Greifswald, Greifswald, Germany
- Institute of Marine Biotechnology, Greifswald, Germany
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Sharma SV, Arbach M, Roberts AA, Macdonald CJ, Groom M, Hamilton CJ. Biophysical features of bacillithiol, the glutathione surrogate of Bacillus subtilis and other firmicutes. Chembiochem 2013; 14:2160-8. [PMID: 24115506 PMCID: PMC4065351 DOI: 10.1002/cbic.201300404] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Indexed: 11/28/2022]
Abstract
Bacillithiol (BSH) is the major low-molecular-weight (LMW) thiol in many low-G+C Gram-positive bacteria (Firmicutes). Evidence now emerging suggests that BSH functions as an important LMW thiol in redox regulation and xenobiotic detoxification, analogous to what is already known for glutathione and mycothiol in other microorganisms. The biophysical properties and cellular concentrations of such LMW thiols are important determinants of their biochemical efficiency both as biochemical nucleophiles and as redox buffers. Here, BSH has been characterised and compared with other LMW thiols in terms of its thiol pKa , redox potential and thiol-disulfide exchange reactivity. Both the thiol pKa and the standard thiol redox potential of BSH are shown to be significantly lower than those of glutathione whereas the reactivities of the two compounds in thiol-disulfide reactions are comparable. The cellular concentration of BSH in Bacillus subtilis varied over different growth phases and reached up to 5 mM, which is significantly greater than previously observed from single measurements taken during mid-exponential growth. These results demonstrate that the biophysical characteristics of BSH are distinctively different from those of GSH and that its cellular concentrations can reach levels much higher than previously reported.
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Affiliation(s)
- Sunil V Sharma
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ (UK)
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Cross-functionalities of Bacillus deacetylases involved in bacillithiol biosynthesis and bacillithiol-S-conjugate detoxification pathways. Biochem J 2013; 454:239-47. [PMID: 23758290 DOI: 10.1042/bj20130415] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BshB, a key enzyme in bacillithiol biosynthesis, hydrolyses the acetyl group from N-acetylglucosamine malate to generate glucosamine malate. In Bacillus anthracis, BA1557 has been identified as the N-acetylglucosamine malate deacetylase (BshB); however, a high content of bacillithiol (~70%) was still observed in the B. anthracis ∆BA1557 strain. Genomic analysis led to the proposal that another deacetylase could exhibit cross-functionality in bacillithiol biosynthesis. In the present study, BA1557, its paralogue BA3888 and orthologous Bacillus cereus enzymes BC1534 and BC3461 have been characterized for their deacetylase activity towards N-acetylglucosamine malate, thus providing biochemical evidence for this proposal. In addition, the involvement of deacetylase enzymes is also expected in bacillithiol-detoxifying pathways through formation of S-mercapturic adducts. The kinetic analysis of bacillithiol-S-bimane conjugate favours the involvement of BA3888 as the B. anthracis bacillithiol-S-conjugate amidase (Bca). The high degree of specificity of this group of enzymes for its physiological substrate, along with their similar pH-activity profile and Zn²⁺-dependent catalytic acid-base reaction provides further evidence for their cross-functionalities.
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Importance of bacillithiol in the oxidative stress response of Staphylococcus aureus. Infect Immun 2013; 82:316-32. [PMID: 24166956 DOI: 10.1128/iai.01074-13] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
In Staphylococcus aureus, the low-molecular-weight thiol called bacillithiol (BSH), together with cognate S-transferases, is believed to be the counterpart to the glutathione system of other organisms. To explore the physiological role of BSH in S. aureus, we constructed mutants with the deletion of bshA (sa1291), which encodes the glycosyltransferase that catalyzes the first step of BSH biosynthesis, and fosB (sa2124), which encodes a BSH-S-transferase that confers fosfomycin resistance, in several S. aureus strains, including clinical isolates. Mutation of fosB or bshA caused a 16- to 60-fold reduction in fosfomycin resistance in these S. aureus strains. High-pressure liquid chromatography analysis, which quantified thiol extracts, revealed some variability in the amounts of BSH present across S. aureus strains. Deletion of fosB led to a decrease in BSH levels. The fosB and bshA mutants of strain COL and a USA300 isolate, upon further characterization, were found to be sensitive to H2O2 and exhibited decreased NADPH levels compared with those in the isogenic parents. Microarray analyses of COL and the isogenic bshA mutant revealed increased expression of genes involved in staphyloxanthin synthesis in the bshA mutant relative to that in COL under thiol stress conditions. However, the bshA mutant of COL demonstrated decreased survival compared to that of the parent in human whole-blood survival assays; likewise, the naturally BSH-deficient strain SH1000 survived less well than its BSH-producing isogenic counterpart. Thus, the survival of S. aureus under oxidative stress is facilitated by BSH, possibly via a FosB-mediated mechanism, independently of its capability to produce staphyloxanthin.
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Role of the CpxAR two-component signal transduction system in control of fosfomycin resistance and carbon substrate uptake. J Bacteriol 2013; 196:248-56. [PMID: 24163343 DOI: 10.1128/jb.01151-13] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although fosfomycin is an old antibiotic, it has resurfaced with particular interest. The antibiotic is still effective against many pathogens that are resistant to other commonly used antibiotics. We have found that fosfomycin resistance of enterohemorrhagic Escherichia coli (EHEC) O157:H7 is controlled by the bacterial two-component signal transduction system CpxAR. A cpxA mutant lacking its phosphatase activity results in constitutive activation of its cognate response regulator, CpxR, and fosfomycin resistance. We have shown that fosfomycin resistance requires CpxR because deletion of the cpxR gene in the cpxA mutant restores fosfomycin sensitivity. We have also shown that CpxR directly represses the expression of two genes, glpT and uhpT, which encode transporters that cotransport fosfomycin with their native substrates glycerol-3-phosphate and glucose-6-phosphate, and repression of these genes leads to a decrease in fosfomycin transport into the cpxA mutant. However, the cpxA mutant had an impaired growth phenotype when cultured with glycerol-3-phosphate or glucose-6-phosphate as a sole carbon substrate and was outcompeted by the parent strain, even in nutrient-rich medium. This suggests a trade-off between fosfomycin resistance and the biological fitness associated with carbon substrate uptake. We propose a role for the CpxAR system in the reversible control of fosfomycin resistance. This may be a beneficial strategy for bacteria to relieve the fitness burden that results from fosfomycin resistance in the absence of fosfomycin.
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Gaballa A, Antelmann H, Hamilton CJ, Helmann JD. Regulation of Bacillus subtilis bacillithiol biosynthesis operons by Spx. MICROBIOLOGY-SGM 2013; 159:2025-2035. [PMID: 23894131 DOI: 10.1099/mic.0.070482-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Bacillithiol is the major low molecular mass thiol produced by many firmicutes bacteria, including the model organism Bacillus subtilis and pathogens such as Bacillus anthracis and Staphylococcus aureus. We have previously shown that four genes (bshA, bshB1, bshB2 and bshC) are involved in bacillithiol biosynthesis. Here, we report that these four genes are encoded within three, unlinked operons all expressed from canonical σ(A)-dependent promoters as determined by 5'RACE (rapid amplification of cDNA ends). The bshA and bshB1 genes are embedded within a seven-gene operon additionally including mgsA, encoding methylglyoxal synthase, and the essential genes cca and birA, encoding tRNA nucleotidyltransferase (CCA transferase) and biotin-protein ligase, respectively. The bshB2 gene is co-transcribed with unknown function genes, while bshC is expressed both as part of a two-gene operon (with the upstream putative pantothenate biosynthesis gene ylbQ) and from its own promoter. All three operons are expressed at a reduced level in an spx null mutant, consistent with a direct role of Spx as a transcriptional activator for these operons, and all three operons are induced by the thiol oxidant diamide. In contrast with other Spx-regulated genes characterized to date, the effects of Spx on basal expression and diamide-stimulated expression appear to be independent of Cys10 in the redox centre of Spx. Consistent with the role of Spx as an activator of bacillithiol biosynthetic genes, cellular levels of bacillithiol are reduced several-fold in an spx null mutant.
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Affiliation(s)
- Ahmed Gaballa
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
| | - Haike Antelmann
- Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald, D-17487 Greifswald, Germany
| | - Chris J Hamilton
- School of Pharmacy, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, USA
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Lipson JM, Thomsen M, Moore BS, Clausen RP, La Clair JJ, Burkart MD. A tandem chemoenzymatic methylation by S-adenosyl-L-methionine. Chembiochem 2013; 14:950-3. [PMID: 23650044 DOI: 10.1002/cbic.201300221] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Indexed: 12/14/2022]
Abstract
Keep 'em methylated: The in situ preparation of the cofactor AdoMet was achieved by allowing the biosynthetic enzyme SalL to operate in the reverse direction by presentation of 5'-chloro-5'-deoxyadenosine at low salt concentrations. This reaction was readily coupled with DNA and small molecule methyltransferases to afford a regioselective method for chemo-enzymatic methylation and isotope incorporation.
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Affiliation(s)
- Joseph M Lipson
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA
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Mechanistic studies of FosB: a divalent-metal-dependent bacillithiol-S-transferase that mediates fosfomycin resistance in Staphylococcus aureus. Biochem J 2013; 451:69-79. [PMID: 23256780 DOI: 10.1042/bj20121541] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
FosB is a divalent-metal-dependent thiol-S-transferase implicated in fosfomycin resistance among many pathogenic Gram-positive bacteria. In the present paper, we describe detailed kinetic studies of FosB from Staphylococcus aureus (SaFosB) that confirm that bacillithiol (BSH) is its preferred physiological thiol substrate. SaFosB is the first to be characterized among a new class of enzyme (bacillithiol-S-transferases), which, unlike glutathione transferases, are distributed among many low-G+C Gram-positive bacteria that use BSH instead of glutathione as their major low-molecular-mass thiol. The K(m) values for BSH and fosfomycin are 4.2 and 17.8 mM respectively. Substrate specificity assays revealed that the thiol and amino groups of BSH are essential for activity, whereas malate is important for SaFosB recognition and catalytic efficiency. Metal activity assays indicated that Mn(2+) and Mg(2+) are likely to be the relevant cofactors under physiological conditions. The serine analogue of BSH (BOH) is an effective competitive inhibitor of SaFosB with respect to BSH, but uncompetitive with respect to fosfomycin. Coupled with NMR characterization of the reaction product (BS-fosfomycin), this demonstrates that the SaFosB-catalysed reaction pathway involves a compulsory ordered binding mechanism with fosfomycin binding first followed by BSH which then attacks the more sterically hindered C-1 carbon of the fosfomycin epoxide. Disruption of BSH biosynthesis in S. aureus increases sensitivity to fosfomycin. Together, these results indicate that SaFosB is a divalent-metal-dependent bacillithiol-S-transferase that confers fosfomycin resistance on S. aureus.
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Abstract
SIGNIFICANCE Oxidative stress is widely invoked in inflammation, aging, and complex diseases. To avoid unwanted oxidations, the redox environment of cellular compartments needs to be tightly controlled. The complementary action of oxidoreductases and of high concentrations of low-molecular-weight (LMW) nonprotein thiols plays an essential role in maintaining the redox potential of the cell in balance. RECENT ADVANCES While LMW thiols are central players in an extensive range of redox regulation/metabolism processes, not all organisms use the same thiol cofactors to this effect, as evidenced by the recent discovery of mycothiol (MSH) and bacillithiol (BSH) among different gram-positive bacteria. CRITICAL ISSUES LMW thiol-disulfide exchange processes and their cellular implications are often oversimplified, as only the biology of the free thiols and their symmetrical disulfides is considered. In bacteria under oxidative stress, especially where concentrations of different LMW thiols are comparable [e.g., BSH, coenzyme A (CoA), and cysteine (Cys) in many low-G+C gram-positive bacteria (Firmicutes)], mixed disulfides (e.g., CoASSB and CySSCoA) must surely be major thiol-redox metabolites that need to be taken into consideration. FUTURE DIRECTIONS There are many microorganisms whose LMW thiol-redox buffers have not yet been identified (either bioinformatically or experimentally). Many elements of BSH and MSH redox biochemistry remain to be explored. The fundamental biophysical properties, thiol pK(a) and redox potential, have not yet been determined, and the protein interactome in which the biothiols MSH and BSH are involved needs further exploration.
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Affiliation(s)
- Koen Van Laer
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie (VIB), Brussels, Belgium
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Analysis of mutants disrupted in bacillithiol metabolism in Staphylococcus aureus. Biochem Biophys Res Commun 2013; 436:128-33. [PMID: 23618856 DOI: 10.1016/j.bbrc.2013.04.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 04/02/2013] [Indexed: 01/06/2023]
Abstract
Bacillithiol (BSH), an α-anomeric glycoside of l-cysteinyl-d-glucosaminyl-l-malate, is a major low molecular weight thiol found in low GC Gram-positive bacteria, such as Staphylococcus aureus. Like other low molecular weight thiols, BSH is likely involved in protection against a number of stresses. We examined S. aureus transposon mutants disrupted in each of the three genes associated with BSH biosynthesis. These mutants are sensitive to alkylating stress, oxidative stress, and metal stress indicating that BSH and BSH-dependent enzymes are involved in protection of S. aureus. We further demonstrate that BshB, a deacetylase involved in the second step of BSH biosynthesis, also acts as a BSH conjugate amidase and identify S. aureus USA 300 LAC 2626 as a BSH-S-transferase, which is able to conjugate chlorodinitrobenzene, cerulenin, and rifamycin to BSH.
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Chi BK, Roberts AA, Huyen TTT, Bäsell K, Becher D, Albrecht D, Hamilton CJ, Antelmann H. S-bacillithiolation protects conserved and essential proteins against hypochlorite stress in firmicutes bacteria. Antioxid Redox Signal 2013; 18:1273-95. [PMID: 22938038 PMCID: PMC3584511 DOI: 10.1089/ars.2012.4686] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
AIMS Protein S-bacillithiolations are mixed disulfides between protein thiols and the bacillithiol (BSH) redox buffer that occur in response to NaOCl in Bacillus subtilis. We used BSH-specific immunoblots, shotgun liquid chromatography (LC)-tandem mass spectrometry (MS/MS) analysis and redox proteomics to characterize the S-bacillithiolomes of B. subtilis, B. megaterium, B. pumilus, B. amyloliquefaciens, and Staphylococcus carnosus and also measured the BSH/oxidized bacillithiol disulfide (BSSB) redox ratio after NaOCl stress. RESULTS In total, 54 proteins with characteristic S-bacillithiolation (SSB) sites were identified, including 29 unique proteins and eight proteins conserved in two or more of these bacteria. The methionine synthase MetE is the most abundant S-bacillithiolated protein in Bacillus species after NaOCl exposure. Further, S-bacillithiolated proteins include the translation elongation factor EF-Tu and aminoacyl-tRNA synthetases (ThrS), the DnaK and GrpE chaperones, the two-Cys peroxiredoxin YkuU, the ferredoxin-NADP(+) oxidoreductase YumC, the inorganic pyrophosphatase PpaC, the inosine-5'-monophosphate dehydrogenase GuaB, proteins involved in thiamine biosynthesis (ThiG and ThiM), queuosine biosynthesis (QueF), biosynthesis of aromatic amino acids (AroA and AroE), serine (SerA), branched-chain amino acids (YwaA), and homocysteine (LuxS and MetI). The thioredoxin-like proteins, YphP and YtxJ, are S-bacillithiolated at their active sites, suggesting a function in the de-bacillithiolation process. S-bacillithiolation is accompanied by a two-fold increase in the BSSB level and a decrease in the BSH/BSSB redox ratio in B. subtilis. INNOVATION Many essential and conserved proteins, including the dominant MetE, were identified in the S-bacillithiolome of different Bacillus species and S. carnosus using shotgun-LC-MS/MS analyses. CONCLUSION S-bacillithiolation is a widespread redox control mechanism among Firmicutes bacteria that protects conserved metabolic enzymes and essential proteins against overoxidation.
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Affiliation(s)
- Bui Khanh Chi
- Institute for Microbiology, Ernst-Moritz-Arndt-University of Greifswald, Greifswald, Germany
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Abstract
The nature of the cytosolic iron pool remains largely uncharacterized, although a range of candidate ligands and chaperones have been proposed. Herein an overview is presented of cytosolic non heme and non iron-sulphur cluster protein iron binding sites and the influence of ligands on the redox activity of iron. This analysis leads to the concept of iron(II) glutathione functioning as the labile cytosolic iron pool and offers a means for the selection of iron over manganese in subsequent incorporation into a wide range of iron-dependent enzymes and electron transfer proteins. Glutathione and glutathione-binding glutaredoxins play a critical role in iron sulfur cluster synthesis and Fe(II)GS (iron(II) coordinated by the thiol function of glutathione) is a suitable iron donor for this biosynthetic route. Significantly, both glutathione and glutaredoxins are universally distributed and thus a controlling influence of glutathione on intracellular iron trafficking is likely to be a common feature of the majority of living organisms.
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Affiliation(s)
- Robert C Hider
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, Stamford Street, London SE1 9NH, UK.
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Pöther DC, Gierok P, Harms M, Mostertz J, Hochgräfe F, Antelmann H, Hamilton CJ, Borovok I, Lalk M, Aharonowitz Y, Hecker M. Distribution and infection-related functions of bacillithiol in Staphylococcus aureus. Int J Med Microbiol 2013; 303:114-23. [PMID: 23517692 DOI: 10.1016/j.ijmm.2013.01.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Revised: 01/24/2013] [Accepted: 01/27/2013] [Indexed: 12/17/2022] Open
Abstract
Bacillithiol (Cys-GlcN-malate, BSH) serves as a major low molecular weight thiol in low GC Gram-positive bacteria including Bacillus species and a variety of Staphylococcus aureus strains. These bacteria do not produce glutathione (GSH). In this study, HPLC analyses were used to determine BSH levels in different S. aureus strains. Furthermore, the role of BSH in the resistance against oxidants and antibiotics and its function in virulence was investigated. We and others (Newton, G.L., Fahey, R.C., Rawat, M., 2012. Microbiology 158, 1117-1126) found that BSH is not produced by members of the S. aureus NCTC8325 lineage, such as strains 8325-4 and SH1000. Using bioinformatics we show that the BSH-biosynthetic gene bshC is disrupted by an 8-bp duplication in S. aureus NCTC8325. The functional bshC-gene from BSH-producing S. aureus Newman (NWMN_1087) was expressed in S. aureus 8325-4 to reconstitute BSH-synthesis. Comparison of the BSH-producing and BSH-minus strains revealed higher resistance of the BSH-producing strain against the antibiotic fosfomycin and the oxidant hypochlorite but not against hydrogen peroxide or diamide. In addition, a higher bacterial load of the BSH-producing strain was detected in human upper-airway epithelial cells and murine macrophages. This indicates a potential role of BSH in protection of S. aureus during infection.
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Affiliation(s)
- Dierk-Christoph Pöther
- Institute of Microbiology, Ernst-Moritz-Arndt-University of Greifswald, 17487 Greifswald, Germany
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Fahey RC. Glutathione analogs in prokaryotes. Biochim Biophys Acta Gen Subj 2012; 1830:3182-98. [PMID: 23075826 DOI: 10.1016/j.bbagen.2012.10.006] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 09/25/2012] [Accepted: 10/08/2012] [Indexed: 01/17/2023]
Abstract
BACKGROUND Oxygen is both essential and toxic to all forms of aerobic life and the chemical versatility and reactivity of thiols play a key role in both aspects. Cysteine thiol groups have key catalytic functions in enzymes but are readily damaged by reactive oxygen species (ROS). Low-molecular-weight thiols provide protective buffers against the hazards of ROS toxicity. Glutathione is the small protective thiol in nearly all eukaryotes but in prokaryotes the situation is far more complex. SCOPE OF REVIEW This review provides an introduction to the diversity of low-molecular-weight thiol protective systems in bacteria. The topics covered include the limitations of cysteine as a protector, the multiple origins and distribution of glutathione biosynthesis, mycothiol biosynthesis and function in Actinobacteria, recent discoveries involving bacillithiol found in Firmicutes, new insights on the biosynthesis and distribution of ergothioneine, and the potential protective roles played by coenzyme A and other thiols. MAJOR CONCLUSIONS Bacteria have evolved a diverse collection of low-molecular-weight protective thiols to deal with oxygen toxicity and environmental challenges. Our understanding of how many of these thiols are produced and utilized is still at an early stage. GENERAL SIGNIFICANCE Extensive diversity existed among prokaryotes prior to evolution of the cyanobacteria and the development of an oxidizing atmosphere. Bacteria that managed to adapt to life under oxygen evolved, or acquired, the ability to produce a variety of small thiols for protection against the hazards of aerobic metabolism. Many pathogenic prokaryotes depend upon novel thiol protection systems that may provide targets for new antibacterial agents. This article is part of a Special Issue entitled Cellular functions of glutathione.
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Affiliation(s)
- Robert C Fahey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.
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Lamers AP, Keithly ME, Kim K, Cook PD, Stec DF, Hines KM, Sulikowski GA, Armstrong RN. Synthesis of bacillithiol and the catalytic selectivity of FosB-type fosfomycin resistance proteins. Org Lett 2012; 14:5207-9. [PMID: 23030527 DOI: 10.1021/ol302327t] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacillithiol (BSH) has been prepared on the gram scale from the inexpensive starting material, D-glucosamine hydrochloride, in 11 steps and 8-9% overall yield. The BSH was used to survey the substrate and metal-ion selectivity of FosB enzymes from four Gram-positive microorganisms associated with the deactivation of the antibiotic fosfomycin. The in vitro results indicate that the preferred thiol substrate and metal ion for the FosB from Staphylococcus aureus are BSH and Ni(II), respectively. However, the metal-ion selectivity is less distinct with FosB from Bacillus subtilis, Bacillus anthracis, or Bacillus cereus.
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Affiliation(s)
- Alexander P Lamers
- Department of Chemistry, Vanderbilt University, Vanderbilt Institute of Chemical Biology, Nashville, Tennessee 37235, USA
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Upton H, Newton GL, Gushiken M, Lo K, Holden D, Fahey RC, Rawat M. Characterization of BshA, bacillithiol glycosyltransferase from Staphylococcus aureus and Bacillus subtilis. FEBS Lett 2012; 586:1004-8. [PMID: 22569254 DOI: 10.1016/j.febslet.2012.02.028] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 02/14/2012] [Accepted: 02/17/2012] [Indexed: 11/26/2022]
Abstract
The first step during bacillithiol (BSH) biosynthesis involves the formation of N-acetylglucosaminylmalate from UDP-N-acetylglucosamine and l-malate and is catalyzed by a GT4 class glycosyltransferase enzyme (BshA). Recombinant Staphylococcus aureus and Bacillus subtilis BshA were highly specific and active with l-malate but the former showed low activity with d-glyceric acid and the latter with d-malate. We show that BshA is inhibited by BSH and similarly that MshA (first enzyme of mycothiol biosynthesis) is inhibited by the final product MSH.
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Affiliation(s)
- Heather Upton
- Department of Biology, California State University-Fresno, Fresno, CA 93740, USA
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41
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Newton GL, Fahey RC, Rawat M. Detoxification of toxins by bacillithiol in Staphylococcus aureus. MICROBIOLOGY-SGM 2012; 158:1117-1126. [PMID: 22262099 DOI: 10.1099/mic.0.055715-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Bacillithiol (BSH), an α-anomeric glycoside of l-cysteinyl-d-glucosaminyl-l-malate, is a major low-molecular-mass thiol found in bacteria such as Bacillus sp., Staphylococcus aureus and Deinococcus radiodurans. Like other low-molecular-mass thiols such as glutathione and mycothiol, BSH is likely to be involved in protection against environmental toxins including thiol-reactive antibiotics. We report here a BSH-dependent detoxification mechanism in S. aureus. When S. aureus Newman strain was treated with monobromobimane and monochlorobimane, the cellular BSH was converted to the fluorescent S-conjugate BS-bimane. A bacillithiol conjugate amidase activity acted upon the BS-bimane to produce Cys-bimane, which was then acetylated by an N-acetyltransferase to generate N-acetyl-Cys-bimane, a mercapturic acid. An S. aureus mutant lacking BSH did not produce mercapturic acid when treated with monobromobimane and monochlorobimane, confirming the involvement of bacillithiol. Furthermore, treatment of S. aureus Newman with rifamycin, the parent compound of the first-line anti-tuberculosis drug, rifampicin, indicated that this thiol-reactive antibiotic is also detoxified in a BSH-dependent manner, since mercapturic acids of rifamycin were observed in the culture medium. These data indicate that toxins and thiol-reactive antibiotics are detoxified to less potent mercapturic acids in a BSH-dependent manner and then exported out of the cell in S. aureus.
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Affiliation(s)
- Gerald L Newton
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Robert C Fahey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Mamta Rawat
- Department of Biology, California State University-Fresno, Fresno, CA 93740, USA
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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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