1
|
Bassett B, Waibel B, White A, Hansen H, Stephens D, Koelper A, Larsen EM, Kim C, Glanzer A, Lavis LD, Hoops GC, Johnson RJ. Measuring the Global Substrate Specificity of Mycobacterial Serine Hydrolases Using a Library of Fluorogenic Ester Substrates. ACS Infect Dis 2018; 4:904-911. [PMID: 29648787 PMCID: PMC5993602 DOI: 10.1021/acsinfecdis.7b00263] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Among the proteins required for lipid metabolism in Mycobacterium tuberculosis are a significant number of uncharacterized serine hydrolases, especially lipases and esterases. Using a streamlined synthetic method, a library of immolative fluorogenic ester substrates was expanded to better represent the natural lipidomic diversity of Mycobacterium. This expanded fluorogenic library was then used to rapidly characterize the global structure activity relationship (SAR) of mycobacterial serine hydrolases in M. smegmatis under different growth conditions. Confirmation of fluorogenic substrate activation by mycobacterial serine hydrolases was performed using nonspecific serine hydrolase inhibitors and reinforced the biological significance of the SAR. The hydrolases responsible for the global SAR were then assigned using gel-resolved activity measurements, and these assignments were used to rapidly identify the relative substrate specificity of previously uncharacterized mycobacterial hydrolases. These measurements provide a global SAR of mycobacterial hydrolase activity, a picture of cycling hydrolase activity, and a detailed substrate specificity profile for previously uncharacterized hydrolases.
Collapse
Affiliation(s)
- Braden Bassett
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Brent Waibel
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Alex White
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Heather Hansen
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Dominique Stephens
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Andrew Koelper
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Erik M. Larsen
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Charles Kim
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147-2439 (USA)
| | - Adam Glanzer
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - Luke D. Lavis
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Dr., Ashburn, VA 20147-2439 (USA)
| | - Geoffrey C. Hoops
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| | - R. Jeremy Johnson
- Department of Chemistry and Biochemistry, Butler University, 4600 Sunset Ave., Indianapolis, IN 46208-3443 (USA)
| |
Collapse
|
2
|
Singh AR, Strankman A, Orkusyan R, Purwantini E, Rawat M. Lack of mycothiol and ergothioneine induces different protective mechanisms in Mycobacterium smegmatis. Biochem Biophys Rep 2016; 8:100-106. [PMID: 28220152 PMCID: PMC5315357 DOI: 10.1016/j.bbrep.2016.08.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Mycobacterium smegmatis contains the low molecular weight thiols, mycothiol (MSH) and ergothioneine (ESH). Examination of transposon mutants disrupted in mshC and egtA, involved in the biosynthesis of MSH and ESH respectively, demonstrated that both mutants were sensitive to oxidative, alkylating, and metal stress. However, the mshC mutant exhibited significantly more protein carbonylation and lipid peroxidation than wildtype, while the egtA mutant had less protein and lipid damage than wildtype. We further show that Ohr, KatN, and AhpC, involved in protection against oxidative stress, are upregulated in the egtA mutant. In the mshC mutant, an Usp and a putative thiol peroxidase are upregulated. In addition, mutants lacking MSH also contained higher levels of Coenzyme F420 as compared to wildtype and two Coenzyme F420 dependent enzymes were found to be upregulated. These results indicate that lack of MSH and ESH result in induction of different mechanisms for protecting against oxidative stress.
Collapse
Affiliation(s)
| | - Andrew Strankman
- Department of Biology, California State University, Fresno, Fresno, CA 93740, United States
| | - Ruzan Orkusyan
- Department of Biology, California State University, Fresno, Fresno, CA 93740, United States
| | - Endang Purwantini
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
| | - Mamta Rawat
- Department of Biology, California State University, Fresno, Fresno, CA 93740, United States
- Corresponding author.
| |
Collapse
|
3
|
Vargas D, Hageman S, Gulati M, Nobile CJ, Rawat M. S-nitrosomycothiol reductase and mycothiol are required for survival under aldehyde stress and biofilm formation in Mycobacterium smegmatis. IUBMB Life 2016; 68:621-8. [PMID: 27321674 DOI: 10.1002/iub.1524] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/11/2016] [Accepted: 05/17/2016] [Indexed: 01/16/2023]
Abstract
We show that Mycobacterium smegmatis mutants disrupted in mscR, coding for a dual function S-nitrosomycothiol reductase and formaldehyde dehydrogenase, and mshC, coding for a mycothiol ligase and lacking mycothiol (MSH), are more susceptible to S-nitrosoglutathione (GSNO) and aldehydes than wild type. MSH is a cofactor for MscR, and both mshC and mscR are induced by GSNO and aldehydes. We also show that a mutant disrupted in egtA, coding for a γ-glutamyl cysteine synthetase and lacking in ergothioneine, is sensitive to nitrosative stress but not to aldehydes. In addition, we find that MSH and S-nitrosomycothiol reductase are required for normal biofilm formation in M. smegmatis, suggesting potential new therapeutic pathways to target to inhibit or disrupt biofilm formation. © 2016 IUBMB Life, 68(8):621-628, 2016.
Collapse
Affiliation(s)
- Derek Vargas
- Department of Biology, California State University-Fresno, Fresno, CA, USA
| | - Samantha Hageman
- Department of Biology, California State University-Fresno, Fresno, CA, USA
| | - Megha Gulati
- Department of Molecular and Cell Biology, University of California Merced, Merced, CA, USA
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California Merced, Merced, CA, USA
| | - Mamta Rawat
- Department of Biology, California State University-Fresno, Fresno, CA, USA
| |
Collapse
|
4
|
Viswanathan G, Joshi SV, Sridhar A, Dutta S, Raghunand TR. Identifying novel mycobacterial stress associated genes using a random mutagenesis screen in Mycobacterium smegmatis. Gene 2015. [PMID: 26211627 DOI: 10.1016/j.gene.2015.07.063] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cell envelope associated components of Mycobacterium tuberculosis (M.tb) have been implicated in stress response, immune modulation and in vivo survival of the pathogen. Although many such factors have been identified, there is a large disparity between the number of genes predicted to be involved in functions linked to the envelope and those described in the literature. To identify and characterise novel stress related factors associated with the mycobacterial cell envelope, we isolated colony morphotype mutants of Mycobacterium smegmatis (M. smegmatis), based on the hypothesis that mutants with unusual colony morphology may have defects in the biosynthesis of cell envelope components. On testing their susceptibility to stress conditions relevant to M.tb physiology, multiple mutants were found to be sensitive to Isoniazid, Diamide and H2O2, indicative of altered permeability due to changes in cell envelope composition. Two mutants showed defects in biofilm formation implying possible roles for the target genes in antibiotic tolerance and/or virulence. These assays identified novel stress associated roles for several mycobacterial genes including sahH, tatB and aceE. Complementation analysis of selected mutants with the M. smegmatis genes and their M.tb homologues showed phenotypic restoration, validating their link to the observed phenotypes. A mutant carrying an insertion in fhaA encoding a forkhead associated domain containing protein, showed reduced survival in THP-1 macrophages, providing in vivo validation to this screen. Taken together, these results suggest that the M.tb homologues of a majority of the identified genes may play significant roles in the pathogenesis of tuberculosis.
Collapse
Affiliation(s)
| | - Shrilaxmi V Joshi
- CSIR - Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India
| | - Aditi Sridhar
- CSIR - Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India
| | - Sayantanee Dutta
- CSIR - Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad, India
| | | |
Collapse
|
5
|
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: 263] [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.
Collapse
|
6
|
Abstract
The pseudodisaccharide mycothiol is present in millimolar levels as the dominant thiol in most species of Actinomycetales. The primary role of mycothiol is to maintain the intracellular redox homeostasis. As such, it acts as an electron acceptor/donor and serves as a cofactor in detoxification reactions for alkylating agents, free radicals and xenobiotics. In addition, like glutathione, mycothiol may be involved in catabolic processes with an essential role for growth on recalcitrant chemicals such as aromatic compounds. Following a little over a decade of research since the discovery of mycothiol in 1994, we summarize the current knowledge about the role of mycothiol as an enzyme cofactor and consider possible mycothiol-dependent enzymes.
Collapse
Affiliation(s)
- Mamta Rawat
- Department of Biology, California State University - Fresno, Fresno, California 93704, USA.
| | | |
Collapse
|
7
|
Dosanjh NS, Rawat M, Chung JH, Av-Gay Y. Thiol specific oxidative stress response inMycobacteria. FEMS Microbiol Lett 2005; 249:87-94. [PMID: 16006064 DOI: 10.1016/j.femsle.2005.06.004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 05/31/2005] [Accepted: 06/02/2005] [Indexed: 10/25/2022] Open
Abstract
The cellular response of mycobacteria to thiol specific oxidative stress was studied in Mycobacterium bovis BCG cultures. Two-dimensional gel electrophoresis revealed that upon diamide treatment at least 60 proteins were upregulated. Fourteen of these proteins were identified by MALDI-MS; four proteins, AhpC, Tpx, GroEL2, and GroEL1 are functionally related to oxidative stress response; eight proteins, LeuC, LeuD, Rv0224c, Rv3029c, AsnB, Rv2971, PheA and HisH are classified as part of the bacterial intermediary metabolism and respiration pathways; protein EchA14 belong to lipid metabolism, and NrdE, belongs to the mycobacterial information pathway category. Reverse transcription followed by quantitative real time PCR in response to diamide stress demonstrated that protein expression is directly proportional to the corresponding gene transcription.
Collapse
Affiliation(s)
- Nirpjit S Dosanjh
- Department of Medicine, Division of Infectious Diseases, University of British Columbia, Vancouver, BC, Canada V5Z 3J5
| | | | | | | |
Collapse
|