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Zou S, Li X, Huang Y, Zhang B, Tang H, Xue Y, Zheng Y. Properties and biotechnological applications of microbial deacetylase. Appl Microbiol Biotechnol 2023:10.1007/s00253-023-12613-1. [PMID: 37326683 DOI: 10.1007/s00253-023-12613-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/25/2023] [Accepted: 05/31/2023] [Indexed: 06/17/2023]
Abstract
Deacetylases, a class of enzymes that can catalyze the hydrolysis of acetylated substrates to remove the acetyl group, used in producing various products with high qualities, are one of the most influential industrial enzymes. These enzymes are highly specific, non-toxic, sustainable, and eco-friendly biocatalysts. Deacetylases and deacetylated compounds have been widely applicated in pharmaceuticals, medicine, food, and the environment. This review synthetically summarizes deacetylases' sources, characterizations, classifications, and applications. Moreover, the typical structural characteristics of deacetylases from different microbial sources are summarized. We also reviewed the deacetylase-catalyzed reactions for producing various deacetylated compounds, such as chitosan-oligosaccharide (COS), mycothiol, 7-aminocephalosporanic acid (7-ACA), glucosamines, amino acids, and polyamines. It is aimed to expound on the advantages and challenges of deacetylases in industrial applications. Moreover, it also serves perspectives on obtaining promising and innovative biocatalysts for enzymatic deacetylation. KEYPOINTS: • The fundamental properties of microbial deacetylases of various microorganisms are presented. • The biochemical characterizations, structures, and catalyzation mechanisms of microbial deacetylases are summarized. • The applications of microbial deacetylases in food, pharmaceutical, medicine, and the environment were discussed.
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Affiliation(s)
- Shuping Zou
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Xia Li
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yinfeng Huang
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Bing Zhang
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Heng Tang
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
| | - Yaping Xue
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China.
| | - Yuguo Zheng
- National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
- Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, People's Republic of China
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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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Guo Y, Gong W, Wang L, Guo J, Jin G, Gu G, Guo Z. Characterization and biochemical investigation of the potential inositol monophosphate phosphatase involved in bacterial mycothiol biosynthesis. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2018.1559326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Yuchuan Guo
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan, China
- Department of Chemistry, University of Florida, Gainesville, USA
| | - Wei Gong
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan, China
| | - Lizhen Wang
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan, China
| | - Jiatong Guo
- Department of Chemistry, University of Florida, Gainesville, USA
| | - Guoxia Jin
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan, China
| | - Guofeng Gu
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan, China
| | - Zhongwu Guo
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, Jinan, China
- Department of Chemistry, University of Florida, Gainesville, USA
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GlcNAc De- N-Acetylase from the Hyperthermophilic Archaeon Sulfolobus solfataricus. Appl Environ Microbiol 2019; 85:AEM.01879-18. [PMID: 30446550 DOI: 10.1128/aem.01879-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/04/2018] [Indexed: 01/17/2023] Open
Abstract
Sulfolobus solfataricus is an aerobic crenarchaeal hyperthermophile with optimum growth at temperatures greater than 80°C and pH 2 to 4. Within the crenarchaeal group of Sulfolobales, N-acetylglucosamine (GlcNAc) has been shown to be a component of exopolysaccharides, forming their biofilms, and of the N-glycan decorating some proteins. The metabolism of GlcNAc is still poorly understood in Archaea, and one approach to gaining additional information is through the identification and functional characterization of carbohydrate active enzymes (CAZymes) involved in the modification of GlcNAc. The screening of S. solfataricus extracts allowed the detection of a novel α-N-acetylglucosaminidase (α-GlcNAcase) activity, which has never been identified in Archaea Mass spectrometry analysis of the purified activity showed a protein encoded by the sso2901 gene. Interestingly, the purified recombinant enzyme, which was characterized in detail, revealed a novel de-N-acetylase activity specific for GlcNAc and derivatives. Thus, assays to identify an α-GlcNAcase found a GlcNAc de-N-acetylase instead. The α-GlcNAcase activity observed in S. solfataricus extracts did occur when SSO2901 was used in combination with an α-glucosidase. Furthermore, the inspection of the genomic context and the preliminary characterization of a putative glycosyltransferase immediately upstream of sso2901 (sso2900) suggest the involvement of these enzymes in the GlcNAc metabolism in S. solfataricus IMPORTANCE In this study, a preliminary screening of cellular extracts of S. solfataricus allowed the identification of an α-N-acetylglucosaminidase activity. However, the characterization of the corresponding recombinant enzyme revealed a novel GlcNAc de-N-acetylase, which, in cooperation with the α-glucosidase, catalyzed the hydrolysis of O-α-GlcNAc glycosides. In addition, we show that the product of a gene flanking the one encoding the de-N-acetylase is a putative glycosyltransferase, suggesting the involvement of the two enzymes in the metabolism of GlcNAc. The discovery and functional analysis of novel enzymatic activities involved in the modification of this essential sugar represent a powerful strategy to shed light on the physiology and metabolism of Archaea.
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Guo Y, Wang L, Guo J, Gu G, Guo Z. Biochemical studies of inositol N-acetylglucosaminyltransferase involved in mycothiol biosynthesis in Corynebacterium diphtheria. Org Biomol Chem 2017; 15:3775-3782. [DOI: 10.1039/c7ob00555e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
First-time expression, isolation, biochemical characterization, and mutagenesis studies of a MshA from Corynebacterium diphtheria involved in its mycothiol biosynthesis.
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Affiliation(s)
- Yuchuan Guo
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology
- Shandong University
- Jinan 250100
- China
- Department of Chemistry
| | - Lizhen Wang
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology
- Shandong University
- Jinan 250100
- China
| | - Jiatong Guo
- Department of Chemistry
- University of Florida
- Gainesville
- USA
| | - Guofeng Gu
- National Glycoengineering Research Center and Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology
- Shandong University
- Jinan 250100
- China
| | - Zhongwu Guo
- Department of Chemistry
- University of Florida
- Gainesville
- USA
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Huang X, Hernick M. Automated docking studies provide insights into molecular determinants of ligand recognition by N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB). Biopolymers 2016; 101:406-17. [PMID: 24037975 DOI: 10.1002/bip.22397] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/19/2013] [Accepted: 08/20/2013] [Indexed: 11/10/2022]
Abstract
The metal-dependent deacetylase N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) catalyzes the deacetylation of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside (GlcNAc-Ins), the committed step in mycothiol (MSH) biosynthesis. MSH is the thiol redox buffer used by mycobacteria to protect against oxidative damage and is involved in the detoxification of xenobiotics. As such, MshB is a target for the discovery of new drugs to treat tuberculosis (TB). While MshB substrate specificity and inhibitor activity have been probed extensively using enzyme kinetics, information regarding the molecular basis for the observed differences in substrate specificity and inhibitor activity is lacking. Herein we begin to examine the molecular determinants of MshB substrate specificity using automated docking studies with a set of known MshB substrates. Results from these studies offer insights into molecular recognition by MshB via identification of side chains and dynamic loops that may play roles in ligand binding. Additionally, results from these studies suggest that a hydrophobic cavity adjacent to the active site may be one important determinant of MshB substrate specificity. Importantly, this hydrophobic cavity may be advantageous for the design of MshB inhibitors with high affinity and specificity as potential TB drugs.
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Affiliation(s)
- Xinyi Huang
- Department of Biochemistry, Virginia Tech, Blacksburg, VA, 24061
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Biosynthesis of mercapturic acid derivative of the labdane-type diterpene, cyslabdan that potentiates imipenem activity against methicillin-resistant Staphylococcus aureus: cyslabdan is generated by mycothiol-mediated xenobiotic detoxification. ACTA ACUST UNITED AC 2016; 43:325-42. [DOI: 10.1007/s10295-015-1694-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/21/2015] [Indexed: 01/20/2023]
Abstract
Abstract
Genome mining of cyslabdan-producing Streptomyces cyslabdanicus K04-0144 revealed that a set of four genes, cldA, cldB, cldC, and cldD (the cld cluster), which formed a single transcriptional unit, were involved in the biosynthesis of cyslabdan that potentiates imipenem activity against methicillin-resistant Staphylococcus aureus. Experimental studies supported the heterologous expression of the cld cluster of S. cyslabdanicus K04-0144 in S. avermitilis SUKA22, and transformants carrying the cld cluster produced not only cyslabdan A (1), but also its new derivatives, 17-hydroxyl-1 (2) and 2-hydroxyl-1 (3), in the culture broth. An analysis of diterpene metabolites in the mycelia showed that a large amount of a novel intermediate had accumulated and its structure was elucidated as (7S, 8S, 12E)-8,17-epoxy-7-hydroxylabda-12,14-diene (4). The cld-like cluster (rmn cluster) was also detected in the genome of S. anulatus GM95 by searching our in-house genome databases, and the heterologous expression of the rmn cluster in S. avermitilis SUAK22 demonstrated that the rmn cluster was involved in the biosynthesis of the labdane-type bicyclic diterpene, raimonol (7). CldA/RmnA catalyzed the generation of geranylgeranyl diphosphate (GGPP) from dimethylallyl diphosphate and isopentenyl diphosphate. CldB/RmnB converted GGPP to (+)-copalyl diphosphate, and CldD/RmnD generated labda-8(17),12(E),14-triene (5). CldC introduced two oxygen atoms at C-7 and C-8,17 to generate 4, while RmnC hydroxylated 5 at C-7 to generate 7. The heterologous expression of the cld cluster suggested that four gene products catalyzed to generate 4, but not 1. The deletion mutant of the gene encoding the mycothiol (MSH)-S-conjugate amidase (mca) of S. avermitilis SUKA22 carrying the cld cluster failed to produce 1, but accumulated 4 in the mycelia, whereas S. avermitilis SUKA22 and its mca-deletion mutant carrying the cld cluster both produced the MSH-S-conjugate of 4. The intermediate 4 was converted into the MSH-S-conjugate with MSH, which was achieved through a non-enzymatic nucleophilic reaction. The MSH-S-conjugate of 4 generated was further hydrolyzed to generate the mercapturic acid derivative, 1, by MSH-S-conjugate amidase and 1 was excreted from the mycelia.
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Favrot L, Blanchard JS, Vergnolle O. Bacterial GCN5-Related N-Acetyltransferases: From Resistance to Regulation. Biochemistry 2016; 55:989-1002. [PMID: 26818562 DOI: 10.1021/acs.biochem.5b01269] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The GCN5-related N-acetyltransferases family (GNAT) is an important family of proteins that includes more than 100000 members among eukaryotes and prokaryotes. Acetylation appears as a major regulatory post-translational modification and is as widespread as phosphorylation. N-Acetyltransferases transfer an acetyl group from acetyl-CoA to a large array of substrates, from small molecules such as aminoglycoside antibiotics to macromolecules. Acetylation of proteins can occur at two different positions, either at the amino-terminal end (αN-acetylation) or at the ε-amino group (εN-acetylation) of an internal lysine residue. GNAT members have been classified into different groups on the basis of their substrate specificity, and in spite of a very low primary sequence identity, GNAT proteins display a common and conserved fold. This Current Topic reviews the different classes of bacterial GNAT proteins, their functions, their structural characteristics, and their mechanism of action.
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Affiliation(s)
- Lorenza Favrot
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - John S Blanchard
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
| | - Olivia Vergnolle
- Department of Biochemistry, Albert Einstein College of Medicine , 1300 Morris Park Avenue, Bronx, New York 10461, United States
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Perera VR, Newton GL, Pogliano K. Bacillithiol: a key protective thiol in Staphylococcus aureus. Expert Rev Anti Infect Ther 2015; 13:1089-107. [PMID: 26184907 DOI: 10.1586/14787210.2015.1064309] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacillithiol is a low-molecular-weight thiol analogous to glutathione and is found in several Firmicutes, including Staphylococcus aureus. Since its discovery in 2009, bacillithiol has been a topic of interest because it has been found to contribute to resistance during oxidative stress and detoxification of electrophiles, such as the antibiotic fosfomycin, in S. aureus. The rapid increase in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to available therapeutic agents is a great health concern, and many research efforts are focused on identifying new drugs and targets to combat this organism. This review describes the discovery of bacillithiol, studies that have elucidated the physiological roles of this molecule in S. aureus and other Bacilli, and the contribution of bacillithiol to S. aureus fitness during pathogenesis. Additionally, the bacillithiol biosynthesis pathway is evaluated as a novel drug target that can be utilized in combination with existing therapies to treat S. aureus infections.
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Affiliation(s)
- Varahenage R Perera
- Division of Biological Sciences, University of California at San Diego, 9500 Gilman Drive, Natural Sciences Building 4113, La Jolla, CA 92093-0377, USA
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Romero JM, Martin M, Ramirez CL, Dumas VG, Marti MA. Efficient Calculation of Enzyme Reaction Free Energy Profiles Using a Hybrid Differential Relaxation Algorithm: Application to Mycobacterial Zinc Hydrolases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 100:33-65. [PMID: 26415840 DOI: 10.1016/bs.apcsb.2015.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
Determination of the free energy profile for an enzyme reaction mechanism is of primordial relevance, paving the way for our understanding of the enzyme's catalytic power at the molecular level. Although hybrid, mostly DFT-based, QM/MM methods have been extensively applied to this type of studies, achieving accurate and statistically converged results at a moderate computational cost is still an open challenge. Recently, we have shown that accurate results can be achieved in less computational time, combining Jarzynski's relationship with a hybrid differential relaxation algorithm (HyDRA), which allows partial relaxation of the solvent during the nonequilibrium steering of the reaction. In this work, we have applied this strategy to study two mycobacterial zinc hydrolases. Mycobacterium tuberculosis infections are still a worldwide problem and thus characterization and validation of new drug targets is an intense field of research. Among possible drug targets, recently two essential zinc hydrolases, MshB (Rv1170) and MA-amidase (Rv3717), have been proposed and structurally characterized. Although possible mechanisms have been proposed by analogy to the widely studied human Zn hydrolases, several key issues, particularly those related to Zn coordination sphere and its role in catalysis, remained unanswered. Our results show that mycobacterial Zn hydrolases share a basic two-step mechanism. First, the attacking water becomes deprotonated by the conserved base and establishes the new C-O bond leading to a tetrahedral intermediate. The intermediate requires moderate reorganization to allow for proton transfer to the amide N and C-N bond breaking to occur in the second step. Zn ion plays a key role in stabilizing the tetrahedral intermediate and balancing the negative charge of the substrate during hydroxide ion attack. Finally, comparative analysis of other Zn hydrolases points to a convergent mechanistic evolution.
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Affiliation(s)
- Juan Manuel Romero
- Instituto de Química Física de los Materiales Medio Ambiente y Energía (INQUIMAE), UBA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Mariano Martin
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Claudia Lilián Ramirez
- Instituto de Química Física de los Materiales Medio Ambiente y Energía (INQUIMAE), UBA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Victoria Gisel Dumas
- Instituto de Química Física de los Materiales Medio Ambiente y Energía (INQUIMAE), UBA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
| | - Marcelo Adrián Marti
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina; Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Ciudad Universitaria, Buenos Aires, Argentina.
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Huang X, Hernick M. Molecular Determinants of N-Acetylglucosamine Recognition and Turnover by N-Acetyl-1-d-myo-inosityl-2-amino-2-deoxy-α-d-glucopyranoside Deacetylase (MshB). Biochemistry 2015; 54:3784-90. [DOI: 10.1021/acs.biochem.5b00068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xinyi Huang
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Marcy Hernick
- Department
of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department
of Pharmaceutical Sciences, Appalachian College of Pharmacy, Oakwood, Virginia 24631, United States
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Mendum TA, Wu H, Kierzek AM, Stewart GR. Lipid metabolism and Type VII secretion systems dominate the genome scale virulence profile of Mycobacterium tuberculosis in human dendritic cells. BMC Genomics 2015; 16:372. [PMID: 25956932 PMCID: PMC4425887 DOI: 10.1186/s12864-015-1569-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 04/23/2015] [Indexed: 12/20/2022] Open
Abstract
Background Mycobacterium tuberculosis continues to kill more people than any other bacterium. Although its archetypal host cell is the macrophage, it also enters, and survives within, dendritic cells (DCs). By modulating the behaviour of the DC, M. tuberculosis is able to manipulate the host’s immune response and establish an infection. To identify the M. tuberculosis genes required for survival within DCs we infected primary human DCs with an M. tuberculosis transposon library and identified mutations with a reduced ability to survive. Results Parallel sequencing of the transposon inserts of the surviving mutants identified a large number of genes as being required for optimal intracellular fitness in DCs. Loci whose mutation attenuated intracellular survival included those involved in synthesising cell wall lipids, not only the well-established virulence factors, pDIM and cord factor, but also sulfolipids and PGL, which have not previously been identified as having a direct virulence role in cells. Other attenuated loci included the secretion systems ESX-1, ESX-2 and ESX-4, alongside many PPE genes, implicating a role for ESX-5. In contrast the canonical ESAT-6 family of ESX substrates did not have intra-DC fitness costs suggesting an alternative ESX-1 associated virulence mechanism. With the aid of a gene-nutrient interaction model, metabolic processes such as cholesterol side chain catabolism, nitrate reductase and cysteine-methionine metabolism were also identified as important for survival in DCs. Conclusion We conclude that many of the virulence factors required for survival in DC are shared with macrophages, but that survival in DCs also requires several additional functions, such as cysteine-methionine metabolism, PGLs, sulfolipids, ESX systems and PPE genes. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1569-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tom A Mendum
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Huihai Wu
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Andrzej M Kierzek
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
| | - Graham R Stewart
- Department of Microbial and Cellular Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, UK.
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Si M, Long M, Chaudhry MT, Xu Y, Zhang P, Zhang L, Shen X. Functional characterization of Corynebacterium glutamicum mycothiol S-conjugate amidase. PLoS One 2014; 9:e115075. [PMID: 25514023 PMCID: PMC4267739 DOI: 10.1371/journal.pone.0115075] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 11/18/2014] [Indexed: 11/18/2022] Open
Abstract
The present study focuses on the genetic and biochemical characterization of mycothiol S-conjugate amidase (Mca) of Corynebacterium glutamicum. Recombinant C. glutamicum Mca was heterologously expressed in Escherichia coli and purified to apparent homogeneity. The molecular weight of native Mca protein determined by gel filtration chromatography was 35 kDa, indicating that Mca exists as monomers in the purification condition. Mca showed amidase activity with mycothiol S-conjugate of monobromobimane (MSmB) in vivo while mca mutant lost the ability to cleave MSmB. In addition, Mca showed limited deacetylase activity with N-acetyl-D-glucosamine (GlcNAc) as substrate. Optimum pH for amidase activity was between 7.5 and 8.5, while the highest activity in the presence of Zn2+ confirmed Mca as a zinc metalloprotein. Amino acid residues conserved among Mca family members were located in C. glutamicum Mca and site-directed mutagenesis of these residues indicated that Asp14, Tyr137, His139 and Asp141 were important for activity. The mca deletion mutant showed decreased resistance to antibiotics, alkylating agents, oxidants and heavy metals, and these sensitive phenotypes were recovered in the complementary strain to a great extent. The physiological roles of Mca in resistance to various toxins were further supported by the induced expression of Mca in C. glutamicum under various stress conditions, directly under the control of the stress-responsive extracytoplasmic function-sigma (ECF-σ) factor SigH.
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Affiliation(s)
- Meiru Si
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Mingxiu Long
- College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Muhammad Tausif Chaudhry
- Environmental Analytical Laboratory, National Physical & Standards Laboratory, PCSIR, Islamabad, Pakistan
| | - Yixiang Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Pan Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Lei Zhang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Xihui Shen
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
- * E-mail:
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15
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Abstract
ABSTRACT
During infection,
Mycobacterium tuberculosis
is exposed to a diverse array of microenvironments in the human host, each with its own unique set of redox conditions. Imbalances in the redox environment of the bacillus or the host environment serve as stimuli, which could regulate virulence. The ability of
M. tuberculosis
to evade the host immune response and cause disease is largely owing to the capacity of the mycobacterium to sense changes in its environment, such as host-generated gases, carbon sources, and pathological conditions, and alter its metabolism and redox balance accordingly for survival. In this article we discuss the redox sensors that are, to date, known to be present in
M. tuberculosis
, such as the Dos dormancy regulon, WhiB family, anti-σ factors, and MosR, in addition to the strategies present in the bacillus to neutralize free radicals, such as superoxide dismutases, catalase-peroxidase, thioredoxins, and methionine sulfoxide reductases, among others.
M. tuberculosis
is peculiar in that it appears to have a hierarchy of redox buffers, namely, mycothiol and ergothioneine. We discuss the current knowledge of their biosynthesis, function, and regulation. Ergothioneine is still an enigma, although it appears to have distinct and overlapping functions with mycothiol, which enable it to protect against a wide range of toxic metabolites and free radicals generated by the host. Developing approaches to quantify the intracellular redox status of the mycobacterium will enable us to determine how the redox balance is altered in response to signals and environments that mimic those encountered in the host.
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16
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Liebens V, Defraine V, Van der Leyden A, De Groote VN, Fierro C, Beullens S, Verstraeten N, Kint C, Jans A, Frangipani E, Visca P, Marchal K, Versées W, Fauvart M, Michiels J. A putative de-N-acetylase of the PIG-L superfamily affects fluoroquinolone tolerance in Pseudomonas aeruginosa. Pathog Dis 2014; 71:39-54. [PMID: 24692291 DOI: 10.1111/2049-632x.12174] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/13/2014] [Accepted: 03/21/2014] [Indexed: 11/29/2022] Open
Abstract
A major cause of treatment failure of infections caused by Pseudomonas aeruginosa is the presence of antibiotic-insensitive persister cells. The mechanism of persister formation in P. aeruginosa is largely unknown, and so far, only few genetic determinants have been linked to P. aeruginosa persistence. Based on a previous high-throughput screening, we here present dnpA (de-N-acetylase involved in persistence; gene locus PA14_66140/PA5002) as a new gene involved in noninherited fluoroquinolone tolerance in P. aeruginosa. Fluoroquinolone tolerance of a dnpA mutant is strongly reduced both in planktonic culture and in a biofilm model, whereas overexpression of dnpA in the wild-type strain increases the persister fraction. In addition, the susceptibility of the dnpA mutant to different classes of antibiotics is not affected. dnpA is part of the conserved LPS core oligosaccharide biosynthesis gene cluster. Based on primary sequence analysis, we predict that DnpA is a de-N-acetylase, acting on an unidentified substrate. Site-directed mutagenesis suggests that this enzymatic activity is essential for DnpA-mediated persistence. A transcriptome analysis indicates that DnpA primarily affects the expression of genes involved in surface-associated processes. We discuss the implications of these findings for future antipersister therapies targeted at chronic P. aeruginosa infections.
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Affiliation(s)
- Veerle Liebens
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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17
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Hernick M. Mycothiol: a target for potentiation of rifampin and other antibiotics againstMycobacterium tuberculosis. Expert Rev Anti Infect Ther 2014; 11:49-67. [DOI: 10.1586/eri.12.152] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Nilewar SS, Kathiravan MK. Mycothiol: a promising antitubercular target. Bioorg Chem 2013; 52:62-8. [PMID: 24368170 DOI: 10.1016/j.bioorg.2013.11.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/12/2013] [Accepted: 11/15/2013] [Indexed: 11/30/2022]
Abstract
Tuberculosis (TB) is the world's second commonest cause of death next to HIV/AIDS. The increasing emergence of multi drug resistance and the recalcitrant nature of persistent infections pose an additional challenge for the treatment of TB. Due to the development of resistance to conventional antibiotics there is a need for new therapeutic strategies to combat M. tuberculosis. One such target is Mycothiol (MSH), a major low molecular-mass thiol in mycobacteria, an important cellular anti-oxidant. MSH is present only in actinomycetes and hence is a good target. This review explores mycothiol as a potential target against tuberculosis and various research ongoing worldwide.
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Affiliation(s)
- S S Nilewar
- Sinhgad College of Pharmacy, Vadgoan (BK), Pune 411041, India
| | - M K Kathiravan
- Sinhgad College of Pharmacy, Vadgoan (BK), Pune 411041, India.
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19
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Paritala H, Carroll KS. New targets and inhibitors of mycobacterial sulfur metabolism. Infect Disord Drug Targets 2013; 13:85-115. [PMID: 23808874 PMCID: PMC4332622 DOI: 10.2174/18715265113139990022] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/08/2013] [Indexed: 11/22/2022]
Abstract
The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress made in the development of inhibitors of sulfur metabolism enzymes.
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Affiliation(s)
| | - Kate S. Carroll
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida, 33458, USA
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20
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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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21
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Expression, refolding, and purification of active diacetylchitobiose deacetylase from Pyrococcus horikoshii. Protein Expr Purif 2012; 84:265-9. [DOI: 10.1016/j.pep.2012.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 11/24/2022]
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22
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Lamprecht DA, Muneri NO, Eastwood H, Naidoo KJ, Strauss E, Jardine A. An enzyme-initiated Smiles rearrangement enables the development of an assay of MshB, the GlcNAc-Ins deacetylase of mycothiol biosynthesis. Org Biomol Chem 2012; 10:5278-88. [PMID: 22678300 DOI: 10.1039/c2ob25429h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MshB is the N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-D-glucopyranoside (GlcNAc-Ins) deacetylase active as one of the enzymes involved in the biosynthesis of mycothiol (MSH), a protective low molecular weight thiol present only in Mycobacterium tuberculosis and other actinomycetes. In this study, structural analogues of GlcNAc-Ins in which the inosityl moiety is replaced by a chromophore were synthesized and evaluated as alternate substrates of MshB, with the goal of identifying a compound that would be useful in high-throughput assays of the enzyme. In an unexpected and surprising finding one of the GlcNAc-Ins analogues is shown to undergo a Smiles rearrangement upon MshB-mediated deacetylation, uncovering a free thiol group. We demonstrate that this chemistry can be exploited for the development of the first continuous assay of MshB activity based on the detection of thiol formation by DTNB (Ellman's reagent); such an assay should be ideally suited for the identification of MshB inhibitors by means of high-throughput screens in microplates.
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Affiliation(s)
- Dirk A Lamprecht
- Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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23
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Huang X, Hernick M. Examination of mechanism of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) reveals unexpected role for dynamic tyrosine. J Biol Chem 2012; 287:10424-10434. [PMID: 22315231 DOI: 10.1074/jbc.m111.320184] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Actinomycetes are a group of gram-positive bacteria that includes pathogenic mycobacterial species, such as Mycobacterium tuberculosis. These organisms do not have glutathione and instead utilize the small molecule mycothiol (MSH) as their primary reducing agent and for the detoxification of xenobiotics. Due to these important functions, enzymes involved in MSH biosynthesis and MSH-dependent detoxification are targets for drug development. The metal-dependent deacetylase N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) catalyzes the hydrolysis of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside to form 1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside and acetate in MSH biosynthesis. Herein we examine the chemical mechanism of MshB. We demonstrate that the side chains of Asp-15, Tyr-142, His-144, and Asp-146 are important for catalytic activity. We show that NaF is an uncompetitive inhibitor of MshB, consistent with a metal-water/hydroxide functioning as the reactive nucleophile in the catalytic mechanism. We have previously shown that MshB activity has a bell-shaped dependence on pH with pK(a) values of ∼7.3 and 10.5 (Huang, X., Kocabas, E. and Hernick, M. (2011) J. Biol. Chem. 286, 20275-20282). Mutagenesis experiments indicate that the observed pK(a) values reflect ionization of Asp-15 and Tyr-142, respectively. Together, findings from our studies suggest that MshB functions through a general acid-base pair mechanism with the side chain of Asp-15 functioning as the general base catalyst and His-144 serving as the general acid catalyst, whereas the side chain of Tyr-142 probably assists in polarizing substrate/stabilizing the oxyanion intermediate. Additionally, our results indicate that Tyr-142 is a dynamic side chain that plays key roles in catalysis, modulating substrate binding, chemistry, and product release.
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Affiliation(s)
- Xinyi Huang
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
| | - Marcy Hernick
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061.
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24
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Abstract
Mycobacterium tuberculosis (Mtb) is a metabolically flexible pathogen
that has the extraordinary ability to sense and adapt to the continuously changing host
environment experienced during decades of persistent infection. Mtb is
continually exposed to endogenous reactive oxygen species (ROS) as part of normal aerobic
respiration, as well as exogenous ROS and reactive nitrogen species (RNS) generated by the
host immune system in response to infection. The magnitude of tuberculosis (TB) disease is
further amplified by exposure to xenobiotics from the environment such as cigarette smoke
and air pollution, causing disruption of the intracellular
prooxidant–antioxidant balance. Both oxidative and reductive stresses induce
redox cascades that alter Mtb signal transduction, DNA and RNA synthesis,
protein synthesis and antimycobacterial drug resistance. As reviewed in this article,
Mtb has evolved specific mechanisms to protect itself against
endogenously produced oxidants, as well as defend against host and environmental oxidants
and reductants found specifically within the microenvironments of the lung. Maintaining an
appropriate redox balance is critical to the clinical outcome because several
antimycobacterial prodrugs are only effective upon bioreductive activation. Proper
homeostasis of oxido-reductive systems is essential for Mtb survival,
persistence and subsequent reactivation. The progress and remaining deficiencies in
understanding Mtb redox homeostasis are also discussed.
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25
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Evaluation of NTF1836 as an inhibitor of the mycothiol biosynthetic enzyme MshC in growing and non-replicating Mycobacterium tuberculosis. Bioorg Med Chem 2011; 19:3956-64. [PMID: 21665483 DOI: 10.1016/j.bmc.2011.05.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 05/11/2011] [Accepted: 05/17/2011] [Indexed: 11/21/2022]
Abstract
The mycothiol biosynthesis enzyme MshC catalyzes the ligation of cysteine with the pseudodisaccharide GlcN-Ins and has been identified as an essential enzyme in Mycobacterium tuberculosis. We now report on the development of NTF1836 as a micromolar inhibitor of MshC. Using commercial libraries, we conducted preliminary structure-activity relationship (SAR) studies on NTF1836. Based on this data, NTF1836 and five structurally related compounds showed similar activity towards clinical strains of M. tuberculosis. A gram scale synthesis was developed to provide ample material for biological studies. Using this material, we determined that inhibition of M. tuberculosis growth by NTF1836 was accompanied by a fall in mycothiol and an increase in GlcN-Ins consistent with the targeting of MshC. We also determined that NTF1836 kills non-replicating M. tuberculosis in the carbon starvation model of latency.
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26
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Huang X, Kocabas E, Hernick M. The activity and cofactor preferences of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-alpha-D-glucopyranoside deacetylase (MshB) change depending on environmental conditions. J Biol Chem 2011; 286:20275-82. [PMID: 21507949 DOI: 10.1074/jbc.m111.234229] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Actinomycetes, such as Mycobacterium species, are Gram-positive bacteria that utilize the small molecule mycothiol (MSH) as their primary reducing agent. Consequently, the enzymes involved in MSH biosynthesis are targets for drug development. The metal-dependent enzyme N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase (MshB) catalyzes the hydrolysis of N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside to form 1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside and acetate, the fourth overall step in MSH biosynthesis. Inhibitors of metalloenzymes typically contain a group that binds to the active site metal ion; thus, a comprehensive understanding of the native cofactor(s) of metalloenzymes is critical for the development of biologically effective inhibitors. Herein, we examined the effect of metal ions on the overall activity of MshB and probed the identity of the native cofactor. We found that the activity of MshB follows the trend Fe(2+) > Co(2+) > Zn(2+) > Mn(2+) and Ni(2+). Additionally, our results show that the identity of the cofactor bound to purified MshB is highly dependent on the purification conditions used (aerobic versus anaerobic), as well as the metal ion content of the medium during protein expression. MshB prefers Fe(2+) under anaerobic conditions regardless of the metal ion content of the medium and switches between Fe(2+) and Zn(2+) under aerobic conditions as the metal content of the medium is altered. These results indicate that the cofactor bound to MshB under biological conditions is dependent on environmental conditions, suggesting that MshB may be a cambialistic metallohydrolase that contains a dynamic cofactor. Consequently, biologically effective inhibitors will likely need to dually target Fe(2+)-MshB and Zn(2+)-MshB.
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Affiliation(s)
- Xinyi Huang
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061, USA
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27
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Precise null deletion mutations of the mycothiol synthesis genes reveal their role in isoniazid and ethionamide resistance in Mycobacterium smegmatis. Antimicrob Agents Chemother 2011; 55:3133-9. [PMID: 21502624 DOI: 10.1128/aac.00020-11] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Mycothiol (MSH; AcCys-GlcN-Ins) is the glutathione analogue for mycobacteria. Mutations in MSH biosynthetic genes have been associated with resistance to isoniazid (INH) and ethionamide (ETH) in mycobacteria, but rigorous genetic studies are lacking, and those that have been conducted have yielded different results. In this study, we constructed independent null deletion mutants for all four genes involved in the MSH biosynthesis pathway (mshA, mshB, mshC, and mshD) in Mycobacterium smegmatis and made complementing constructs in integrating plasmids. The resulting set of strains was analyzed for levels of MSH, INH resistance, and ETH resistance. The mshA and mshC single deletion mutants were devoid of MSH production and resistant to INH, whereas the mshB deletion mutant produced decreased levels of MSH yet was sensitive to INH, suggesting that MSH biosynthesis is essential for INH susceptibility in M. smegmatis. Further evidence supporting this conclusion was generated by deleting the gene encoding the MSH S-conjugate amidase (mca) from the ΔmshB null mutant. This double mutant, ΔmshB Δmca, completely abolished MSH production and was resistant to INH. The mshA, mshC, and mshB single deletion mutants were also resistant to ETH, indicating that ETH resistance is modulated by the level of MSH in M. smegmatis. Surprisingly, the mshD deletion mutant lacked MSH production but was sensitive to both INH and ETH. The drug sensitivity was likely mediated by the compensated synthesis of N-formyl-Cys-GlcN-Ins, previously demonstrated to substitute for MSH in an mshD mutant of M. smegmatis. We conclude that MSH or N-formyl-Cys-GlcN-Ins is required for susceptibility to INH or ETH in M. smegmatis.
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28
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A fluorescence-based assay for measuring N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-α-D-glucopyranoside deacetylase activity. Anal Biochem 2011; 414:278-81. [PMID: 21477577 DOI: 10.1016/j.ab.2011.04.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 03/25/2011] [Accepted: 04/01/2011] [Indexed: 11/23/2022]
Abstract
Here we report a new fluorescence-based assay for measuring MshB (N-acetyl-1-d-myo-inosityl-2-amino-2-deoxy-α-d-glucopyranoside deacetylase) activity. The current assay for measuring MshB activity requires the fluorescent labeling of reaction mixtures and subsequent analysis using high-performance liquid chromatography (HPLC), resulting in a significant amount of processing time per sample. Here we describe a more rapid fluorescnce-based assay for the measurement of MshB activity that does not require HPLC analysis and can be carried out in multiwell plates. This fluorescamine (FSA)-based assay was used to determine the steady-state parameters for the deacetylation of N-acetyl-glucosamine (GlcNAc) by MshB, and the results from these experiments support the hypothesis that the inositol moiety primarily contributes to the affinity of GlcNAc-Ins (N-acetyl-1-d-myo-inosityl-2-amino-2-deoxy-α-d-glucopyranoside) for MshB. The rapid nature of this assay will aid efforts toward a more detailed biochemical characterization of MshB. Furthermore, because this assay relies on the formation of a primary amine, it could be adapted to measure the activity of mycothiol-S-conjugate amidase, a metal-dependent amidase that is a potential drug target involved in the mycothiol detoxification pathway.
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29
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Farhana A, Guidry L, Srivastava A, Singh A, Hondalus MK, Steyn AJC. Reductive stress in microbes: implications for understanding Mycobacterium tuberculosis disease and persistence. Adv Microb Physiol 2011; 57:43-117. [PMID: 21078441 DOI: 10.1016/b978-0-12-381045-8.00002-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is a remarkably successful pathogen that is capable of persisting in host tissues for decades without causing disease. Years after initial infection, the bacilli may resume growth, the outcome of which is active tuberculosis (TB). In order to establish infection, resist host defences and re-emerge, Mtb must coordinate its metabolism with the in vivo environmental conditions and nutrient availability within the primary site of infection, the lung. Maintaining metabolic homeostasis for an intracellular pathogen such as Mtb requires a carefully orchestrated series of oxidation-reduction reactions, which, if unbalanced, generate oxidative or reductive stress. The importance of oxidative stress in microbial pathogenesis has been appreciated and well studied over the past several decades. However, the role of its counterpart, reductive stress, has been largely ignored. Reductive stress is defined as an aberrant increase in reducing equivalents, the magnitude and identity of which is determined by host carbon source utilisation and influenced by the presence of host-generated gases (e.g. NO, CO, O(2) and CO(2)). This increased reductive power must be dissipated for bacterial survival. To recycle reducing equivalents, microbes have evolved unique electron 'sinks' that are distinct for their particular environmental niche. In this review, we describe the specific mechanisms that some microbes have evolved to dispel reductive stress. The intention of this review is to introduce the concept of reductive stress, in tuberculosis research in particular, in the hope of stimulating new avenues of investigation.
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Affiliation(s)
- Aisha Farhana
- Department of Microbiology, University of Alabama at Birmingham, AL, USA
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30
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Organic hydroperoxide resistance protein and ergothioneine compensate for loss of mycothiol in Mycobacterium smegmatis mutants. J Bacteriol 2011; 193:1981-90. [PMID: 21335456 DOI: 10.1128/jb.01402-10] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The mshA::Tn5 mutant of Mycobacterium smegmatis does not produce mycothiol (MSH) and was found to markedly overproduce both ergothioneine and an ~15-kDa protein determined to be organic hydroperoxide resistance protein (Ohr). An mshA(G32D) mutant lacking MSH overproduced ergothioneine but not Ohr. Comparison of the mutant phenotypes with those of the wild-type strain indicated the following: Ohr protects against organic hydroperoxide toxicity, whereas ergothioneine does not; an additional MSH-dependent organic hydroperoxide peroxidase exists; and elevated isoniazid resistance in the mutant is associated with both Ohr and the absence of MSH. Purified Ohr showed high activity with linoleic acid hydroperoxide, indicating lipid hydroperoxides as the likely physiologic targets. The reduction of oxidized Ohr by NADH was shown to be catalyzed by lipoamide dehydrogenase and either lipoamide or DlaT (SucB). Since free lipoamide and lipoic acid levels were shown to be undetectable in M. smegmatis, the bound lipoyl residues of DlaT are the likely source of the physiological dithiol reductant for Ohr. The pattern of occurrence of homologs of Ohr among bacteria suggests that the ohr gene has been distributed by lateral transfer. The finding of multiple Ohr homologs with various sequence identities in some bacterial genomes indicates that there may be multiple physiologic targets for Ohr proteins.
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31
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Skovierová H, Larrouy-Maumus G, Pham H, Belanová M, Barilone N, Dasgupta A, Mikusová K, Gicquel B, Gilleron M, Brennan PJ, Puzo G, Nigou J, Jackson M. Biosynthetic origin of the galactosamine substituent of Arabinogalactan in Mycobacterium tuberculosis. J Biol Chem 2010; 285:41348-55. [PMID: 21030587 DOI: 10.1074/jbc.m110.188110] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The arabinogalactan (AG) of slow growing pathogenic Mycobacterium spp. is characterized by the presence of galactosamine (GalN) modifying some of the interior branched arabinosyl residues. The biosynthetic origin of this substituent and its role(s) in the physiology and/or pathogenicity of mycobacteria are not known. We report on the discovery of a polyprenyl-phospho-N-acetylgalactosaminyl synthase (PpgS) and the glycosyltransferase Rv3779 from Mycobacterium tuberculosis required, respectively, for providing and transferring the GalN substrate for the modification of AG. Disruption of either ppgS (Rv3631) or Rv3779 totally abolished the synthesis of the GalN substituent of AG in M. tuberculosis H37Rv. Conversely, expression of ppgS in Mycobacterium smegmatis conferred upon this species otherwise devoid of ppgS ortholog and any detectable polyprenyl-phospho-N-acetylgalactosaminyl synthase activity the ability to synthesize polyprenyl-phospho-N-acetylgalactosamine (polyprenyl-P-GalNAc) from polyprenyl-P and UDP-GalNAc. Interestingly, this catalytic activity was increased 40-50-fold by co-expressing Rv3632, the encoding gene of a small membrane protein apparently co-transcribed with ppgS in M. tuberculosis H37Rv. The discovery of this novel lipid-linked sugar donor and the involvement of a the glycosyltransferase C-type glycosyltransferase in its transfer onto its final acceptor suggest that pathogenic mycobacteria modify AG on the periplasmic side of the plasma membrane. The availability of a ppgS knock-out mutant of M. tuberculosis provides unique opportunities to investigate the physiological function of the GalN substituent and the potential impact it may have on host-pathogen interactions.
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Affiliation(s)
- Henrieta Skovierová
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682, USA
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Ajayi K, Thakur VV, Lapo RC, Knapp S. Intramolecular alpha-glucosaminidation: synthesis of mycothiol. Org Lett 2010; 12:2630-3. [PMID: 20443569 DOI: 10.1021/ol1008334] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A protected cyclitol aglycon was tethered to an (N-arylsulfonyl)glucosamine donor by a methylene linker; the exclusively alpha-selective intramolecular glycosylation reaction was then initiated by electrophilic activation of the thioglycoside donor portion. Further transformations of the glycosylation product to give the M. tuberculosis detoxifier mycothiol and its oxidized congener, the disulfide mycothione, are detailed.
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Affiliation(s)
- Kehinde Ajayi
- Department of Chemistry and Chemical Biology, Rutgers-The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, USA
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33
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Deli A, Koutsioulis D, Fadouloglou VE, Spiliotopoulou P, Balomenou S, Arnaouteli S, Tzanodaskalaki M, Mavromatis K, Kokkinidis M, Bouriotis V. LmbE proteins from Bacillus cereus are de-N-acetylases with broad substrate specificity and are highly similar to proteins in Bacillus anthracis. FEBS J 2010; 277:2740-53. [DOI: 10.1111/j.1742-4658.2010.07691.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Wyszynski FJ, Hesketh AR, Bibb MJ, Davis BG. Dissecting tunicamycin biosynthesis by genome mining: cloning and heterologous expression of a minimal gene cluster. Chem Sci 2010. [DOI: 10.1039/c0sc00325e] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Kaur D, Guerin ME, Skovierová H, Brennan PJ, Jackson M. Chapter 2: Biogenesis of the cell wall and other glycoconjugates of Mycobacterium tuberculosis. ADVANCES IN APPLIED MICROBIOLOGY 2009; 69:23-78. [PMID: 19729090 DOI: 10.1016/s0065-2164(09)69002-x] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The re-emergence of tuberculosis in its present-day manifestations - single, multiple and extensive drug-resistant forms and as HIV-TB coinfections - has resulted in renewed research on fundamental questions such as the nature of the organism itself, Mycobacterium tuberculosis, the molecular basis of its pathogenesis, definition of the immunological response in animal models and humans, and development of new intervention strategies such as vaccines and drugs. Foremost among these developments has been the precise chemical definition of the complex and distinctive cell wall of M. tuberculosis, elucidation of the relevant pathways and underlying genetics responsible for the synthesis of the hallmark moieties of the tubercle bacillus such as the mycolic acid-arabinogalactan-peptidoglycan complex, the phthiocerol- and trehalose-containing effector lipids, the phosphatidylinositol-containing mannosides, lipomannosides and lipoarabinomannosides, major immunomodulators, and others. In this review, the laboratory personnel who have been the focal point of some to these developments review recent progress towards a comprehensive understanding of the basic physiology and functions of the cell wall of M. tuberculosis.
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Affiliation(s)
- Devinder Kaur
- Department of Microbiology, Immunology and Pathology, Mycobacteria Research Laboratories, Colorado State University, Fort Collins, CO 80523-1682, USA
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36
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Fan F, Vetting MW, Frantom PA, Blanchard JS. Structures and mechanisms of the mycothiol biosynthetic enzymes. Curr Opin Chem Biol 2009; 13:451-9. [PMID: 19699138 DOI: 10.1016/j.cbpa.2009.07.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Revised: 07/13/2009] [Accepted: 07/21/2009] [Indexed: 11/27/2022]
Abstract
In the past decade, the genes encoding all four enzymes responsible for the biosynthesis of mycothiol in Mycobacterium tuberculosis have been identified. Orthologs of each of these have been stably expressed and structurally characterized. The chemical mechanisms of all the four have also been studied. Because of the unique phylogenetic distribution of mycothiol, and the enzymes responsible for its biosynthesis, these enzymes represent interesting potential targets for antimycobacterial agents.
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Affiliation(s)
- Fan Fan
- Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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37
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Biosynthesis and functions of mycothiol, the unique protective thiol of Actinobacteria. Microbiol Mol Biol Rev 2008; 72:471-94. [PMID: 18772286 DOI: 10.1128/mmbr.00008-08] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycothiol (MSH; AcCys-GlcN-Ins) is the major thiol found in Actinobacteria and has many of the functions of glutathione, which is the dominant thiol in other bacteria and eukaryotes but is absent in Actinobacteria. MSH functions as a protected reserve of cysteine and in the detoxification of alkylating agents, reactive oxygen and nitrogen species, and antibiotics. MSH also acts as a thiol buffer which is important in maintaining the highly reducing environment within the cell and protecting against disulfide stress. The pathway of MSH biosynthesis involves production of GlcNAc-Ins-P by MSH glycosyltransferase (MshA), dephosphorylation by the MSH phosphatase MshA2 (not yet identified), deacetylation by MshB to produce GlcN-Ins, linkage to Cys by the MSH ligase MshC, and acetylation by MSH synthase (MshD), yielding MSH. Studies of MSH mutants have shown that the MSH glycosyltransferase MshA and the MSH ligase MshC are required for MSH production, whereas mutants in the MSH deacetylase MshB and the acetyltransferase (MSH synthase) MshD produce some MSH and/or a closely related thiol. Current evidence indicates that MSH biosynthesis is controlled by transcriptional regulation mediated by sigma(B) and sigma(R) in Streptomyces coelicolor. Identified enzymes of MSH metabolism include mycothione reductase (disulfide reductase; Mtr), the S-nitrosomycothiol reductase MscR, the MSH S-conjugate amidase Mca, and an MSH-dependent maleylpyruvate isomerase. Mca cleaves MSH S-conjugates to generate mercapturic acids (AcCySR), excreted from the cell, and GlcN-Ins, used for resynthesis of MSH. The phenotypes of MSH-deficient mutants indicate the occurrence of one or more MSH-dependent S-transferases, peroxidases, and mycoredoxins, which are important targets for future studies. Current evidence suggests that several MSH biosynthetic and metabolic enzymes are potential targets for drugs against tuberculosis. The functions of MSH in antibiotic-producing streptomycetes and in bioremediation are areas for future study.
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38
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Newton GL, Fahey RC. An N-acyl homolog of mycothiol is produced in marine actinomycetes. Arch Microbiol 2008; 190:547-57. [PMID: 18629474 PMCID: PMC2574923 DOI: 10.1007/s00203-008-0405-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/13/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
Marine actinomycetes have generated much recent interest as a potentially valuable source of novel antibiotics. Like terrestrial actinomycetes the marine actinomycetes are shown here to produce mycothiol as their protective thiol. However, a novel thiol, U25, was produced by MAR2 strain CNQ703 upon progression into stationary phase when secondary metabolite production occurred and became the dominant thiol. MSH and U25 were maintained in a reduced state during early stationary phase, but become significantly oxidized after 10 days in culture. Isolation and structural analysis of the monobromobimane derivative identified U25 as a homolog of mycothiol in which the acetyl group attached to the nitrogen of cysteine is replaced by a propionyl residue. This N-propionyl-desacetyl-mycothiol was present in 13 of the 17 strains of marine actinomycetes examined, including five strains of Salinispora and representatives of the MAR2, MAR3, MAR4 and MAR6 groups. Mycothiol and its precursor, the pseudodisaccharide 1-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-D-myo-inositol, were found in all strains. High levels of mycothiol S-conjugate amidase activity, a key enzyme in mycothiol-dependent detoxification, were found in most strains. The results demonstrate that major thiol/disulfide changes accompany secondary metabolite production and suggest that mycothiol-dependent detoxification is important at this developmental stage.
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Affiliation(s)
- Gerald L. Newton
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA e-mail: fax: 858-5344864
| | - Robert C. Fahey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA e-mail: fax: 858-5344864
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39
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Jothivasan VK, Hamilton CJ. Mycothiol: synthesis, biosynthesis and biological functions of the major low molecular weight thiol in actinomycetes. Nat Prod Rep 2008; 25:1091-117. [PMID: 19030604 DOI: 10.1039/b616489g] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Actinomycetes produce mycothiol as their major low molecular weight thiol, which parallels the functions of glutathione found in prokaryotes and most Gram-negative bacteria. This review covers progress that has so far been made in terms of its distribution, biosynthesis and metabolic functions, as well as chemical syntheses of mycothiol and alternative substrates and inhibitors of mycothiol biosynthesis and mycothiol-dependent enzymes. 152 references are cited.
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Zou Y, Brunzelle JS, Nair SK. Crystal structures of lipoglycopeptide antibiotic deacetylases: implications for the biosynthesis of A40926 and teicoplanin. ACTA ACUST UNITED AC 2008; 15:533-45. [PMID: 18559264 DOI: 10.1016/j.chembiol.2008.05.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2008] [Revised: 05/02/2008] [Accepted: 05/05/2008] [Indexed: 10/21/2022]
Abstract
The lipoglycopeptide antibiotics teicoplanin and A40926 have proven efficacy against Gram-positive pathogens. These drugs are distinguished from glycopeptide antibiotics by N-linked long chain acyl-D-glucosamine decorations that contribute to antibacterial efficacy. During the biosynthesis of lipoglycopeptides, tailoring glycosyltransferases attach an N-acetyl-D-glucosamine to the aglycone, and this N-acetyl-glucosaminyl pseudoaglycone is deacetylated prior to long chain hydrocarbon attachment. Here we present several high-resolution crystal structures of the pseudoaglycone deacetylases from the biosynthetic pathways of teicoplanin and A40926. The cocrystal structure of the teicoplanin pseudoaglycone deacetylase with a fatty acid product provides further insights into the roles of active-site residues, and suggests mechanistic similarities with structurally distinct zinc deacetylases, such as peptidoglycan deacetylase and LpxC. A unique, structurally mobile capping lid, located at the apex of these pseudoaglycone deacetylases, likely serves as a determinant of substrate specificity.
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Affiliation(s)
- Yaozhong Zou
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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41
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Vilchèze C, Av-Gay Y, Attarian R, Liu Z, Hazbón MH, Colangeli R, Chen B, Liu W, Alland D, Sacchettini JC, Jacobs WR. Mycothiol biosynthesis is essential for ethionamide susceptibility in Mycobacterium tuberculosis. Mol Microbiol 2008; 69:1316-29. [PMID: 18651841 PMCID: PMC2628429 DOI: 10.1111/j.1365-2958.2008.06365.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spontaneous mutants of Mycobacterium tuberculosis that were resistant to the anti-tuberculosis drugs ethionamide and isoniazid were isolated and found to map to mshA, a gene encoding the first enzyme involved in the biosynthesis of mycothiol, a major low-molecular-weight thiol in M. tuberculosis. Seven independent missense or frameshift mutations within mshA were identified and characterized. Precise null deletion mutations of the mshA gene were generated by specialized transduction in three different strains of M. tuberculosis. The mshA deletion mutants were defective in mycothiol biosynthesis, were only ethionamide-resistant and required catalase to grow. Biochemical studies suggested that the mechanism of ethionamide resistance in mshA mutants was likely due to a defect in ethionamide activation. In vivo, a mycothiol-deficient strain grew normally in immunodeficient mice, but was slightly defective for growth in immunocompetent mice. Mutations in mshA demonstrate the non-essentiality of mycothiol for growth in vitro and in vivo, and provide a novel mechanism of ethionamide resistance in M. tuberculosis.
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Affiliation(s)
- Catherine Vilchèze
- Howard Hughes Medical Institute, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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42
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Vetting MW, Frantom PA, Blanchard JS. Structural and enzymatic analysis of MshA from Corynebacterium glutamicum: substrate-assisted catalysis. J Biol Chem 2008; 283:15834-44. [PMID: 18390549 PMCID: PMC2414306 DOI: 10.1074/jbc.m801017200] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 03/26/2008] [Indexed: 11/06/2022] Open
Abstract
The glycosyltransferase termed MshA catalyzes the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to 1-L-myo-inositol-1-phosphate in the first committed step of mycothiol biosynthesis. The structure of MshA from Corynebacterium glutamicum was determined both in the absence of substrates and in a complex with UDP and 1-L-myo-inositol-1-phosphate. MshA belongs to the GT-B structural family whose members have a two-domain structure with both domains exhibiting a Rossman-type fold. Binding of the donor sugar to the C-terminal domain produces a 97 degrees rotational reorientation of the N-terminal domain relative to the C-terminal domain, clamping down on UDP and generating the binding site for 1-L-myo-inositol-1-phosphate. The structure highlights the residues important in binding of UDP-N-acetylglucosamine and 1-L-myo-inositol-1-phosphate. Molecular models of the ternary complex suggest a mechanism in which the beta-phosphate of the substrate, UDP-N-acetylglucosamine, promotes the nucleophilic attack of the 3-hydroxyl group of 1-L-myo-inositol-1-phosphate while at the same time promoting the cleavage of the sugar nucleotide bond.
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Affiliation(s)
- Matthew W Vetting
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
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43
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Park JH, Roe JH. Mycothiol regulates and is regulated by a thiol-specific antisigma factor RsrA and σRin Streptomyces coelicolor. Mol Microbiol 2008; 68:861-70. [DOI: 10.1111/j.1365-2958.2008.06191.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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44
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den Hengst CD, Buttner MJ. Redox control in actinobacteria. Biochim Biophys Acta Gen Subj 2008; 1780:1201-16. [PMID: 18252205 DOI: 10.1016/j.bbagen.2008.01.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 01/07/2008] [Accepted: 01/14/2008] [Indexed: 10/22/2022]
Abstract
As most actinobacteria are obligate aerobes, they have to cope with endogenously generated reactive oxygen species, and actinobacterial pathogens have to resist oxidative attack by phagocytes. Actinobacteria also have to survive long periods under low oxygen tension; for example, Mycobacterium tuberculosis can persist in the host for years under apparently hypoxic conditions in a latent, non-replicative state. Here we focus on the regulatory switches that control actinobacterial responses to peroxide stress, disulfide stress and low oxygen tension. Other unique aspects of their redox biology will be highlighted, including the use of the pseudodisaccharide mycothiol as their major low-molecular-weight thiol buffer, and the [4Fe-4S]-containing WhiB-like proteins, which play diverse, important roles in actinobacterial biology, but whose biochemical role is still controversial.
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Affiliation(s)
- Chris D den Hengst
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Colney, Norwich, NR4 7UH, UK.
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45
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Tomioka H. Development of new antituberculous agents based on new drug targets and structure–activity relationship. Expert Opin Drug Discov 2007; 3:21-49. [DOI: 10.1517/17460441.3.1.21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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46
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Rawat M, Johnson C, Cadiz V, Av-Gay Y. Comparative analysis of mutants in the mycothiol biosynthesis pathway in Mycobacterium smegmatis. Biochem Biophys Res Commun 2007; 363:71-6. [PMID: 17826740 DOI: 10.1016/j.bbrc.2007.08.142] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Accepted: 08/18/2007] [Indexed: 11/16/2022]
Abstract
The role of mycothiol in mycobacteria was examined by comparative analysis of mutants disrupted in the four known genes encoding the protein machinery needed for mycothiol biosynthesis. These mutants were sensitive to acid stress, antibiotic stress, alkylating stress, and oxidative stress indicating that mycothiol and mycothiol-dependent enzymes protect the mycobacterial cell against attack from various different types of stresses and toxic agents.
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Affiliation(s)
- Mamta Rawat
- Department of Biology, California State University-Fresno, Fresno, CA 937401, USA
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47
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Baker EN. Structural genomics as an approach towards understanding the biology of tuberculosis. ACTA ACUST UNITED AC 2007; 8:57-65. [PMID: 17668294 DOI: 10.1007/s10969-007-9020-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Accepted: 07/09/2007] [Indexed: 10/23/2022]
Abstract
Tuberculosis (TB) is a devastating disease of worldwide importance. The availability of the genome sequence of Mycobacterium tuberculosis (Mtb), the causative agent, has stimulated a large variety of genome-scale initiatives. These include international structural genomics efforts which have the dual aim of characterising potential new drug targets and addressing key aspects of the biology of Mtb. This review highlights the various ways in which structural analysis has illuminated the biological activities of Mtb gene products, which were previously of unknown or uncertain function. Key information comes from the protein fold, from bound ligands, solvent molecules, ions etc. or from unexpectedly modified amino acid residues. Most importantly, the three dimensional structure of a protein permits the integration of data from many sources, both bioinformatic and experimental, to develop testable functional hypotheses. This has led to many new insights into TB biology.
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Affiliation(s)
- Edward N Baker
- Maurice Wilkins Centre for Molecular Biodiscovery and School of Biological Sciences, University of Auckland, Auckland, New Zealand.
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48
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Abstract
The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress in the development of inhibitors of sulfur metabolism enzymes.
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Affiliation(s)
- Devayani P. Bhave
- Chemical Biology Ph.D. Program, University of Michigan, Ann Arbor, Michigan, 48109-2216
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109-2216
| | - Wilson B. Muse
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109-2216
| | - Kate S. Carroll
- Chemical Biology Ph.D. Program, University of Michigan, Ann Arbor, Michigan, 48109-2216
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, 48109-2216
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, 48109-2216
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49
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Fadouloglou VE, Deli A, Glykos NM, Psylinakis E, Bouriotis V, Kokkinidis M. Crystal structure of the BcZBP, a zinc-binding protein from Bacillus cereus. FEBS J 2007; 274:3044-54. [PMID: 17501983 DOI: 10.1111/j.1742-4658.2007.05834.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Bacillus cereus is an opportunistic pathogenic bacterium closely related to Bacillus anthracis, the causative agent of anthrax in mammals. A significant portion of the B. cereus chromosomal genes are common to B. anthracis, including genes which in B. anthracis code for putative virulence and surface proteins. B. cereus thus provides a convenient model organism for studying proteins potentially associated with the pathogenicity of the highly infectious B. anthracis. The zinc-binding protein of B. cereus, BcZBP, is encoded from the bc1534 gene which has three homologues to B. anthracis. The protein exhibits deacetylase activity with the N-acetyl moiety of the N-acetylglucosamine and the diacetylchitobiose and triacetylchitotriose. However, neither the specific substrate of the BcZBP nor the biochemical pathway have been conclusively identified. Here, we present the crystal structure of BcZBP at 1.8 A resolution. The N-terminal part of the 234 amino acid protein adopts a Rossmann fold whereas the C-terminal part consists of two beta-strands and two alpha-helices. In the crystal, the protein forms a compact hexamer, in agreement with solution data. A zinc binding site and a potential active site have been identified in each monomer. These sites have extensive similarities to those found in two known zinc-dependent hydrolases with deacetylase activity, MshB and LpxC, despite a low degree of amino acid sequence identity. The functional implications and a possible catalytic mechanism are discussed.
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50
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Truman AW, Huang F, Llewellyn NM, Spencer JB. Characterization of the enzyme BtrD from Bacillus circulans and revision of its functional assignment in the biosynthesis of butirosin. Angew Chem Int Ed Engl 2007; 46:1462-4. [PMID: 17226887 DOI: 10.1002/anie.200604194] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Andrew W Truman
- University of Cambridge, University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK
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