期刊
ARCHIVES OF MICROBIOLOGY
卷 178, 期 6, 页码 388-394出版社
SPRINGER
DOI: 10.1007/s00203-002-0469-4
关键词
mycothiol; mshA; mshB; mshC; mshD; mca; mtr; Mycobacterium tuberculosis; antibiotic detoxification; mercapturic acid
类别
资金
- NIAAA NIH HHS [AA 11393] Funding Source: Medline
- NIAID NIH HHS [AI 49174] Funding Source: Medline
Mycothiol (MSH) is a novel thiol comprised of N-acetylcysteine amide-linked to G1cN-alpha(1-1)-Ins. It is the major thiol in most actinomycetes and is produced at millimolar levels in mycobacteria and streptomycetes. MSH biosynthesis occurs by linkage of G1cNAc to Ins, deacetylation to G1cN-Ins, ligation of the latter to L-cysteine, and transacetylation of the cysteinyl residue by CoASAc to produce MSH. The genes encoding the respective enzymes have been designated mshA, mshB, mshC, and mshD; all but mshA have been identified. Mycobacterium smegmatis mutants deficient in mshA, mshC, and mshD have been characterized. MSH plays a significant role in the detoxification of thiol-reactive substances, including formaldehyde, various electrophiles, and antibiotics. Mycothiol S-conjugates derived from electrophiles and antibiotics are cleaved by mycothiol S-conjugate amidase to release G1cN-Ins, used to resynthesize MSH, and a mercapturic acid which is excreted from the cell. A mycothiol-disulfide-selective reductase has been identified and likely helps to maintain cellular MSH in the reduced state. Mycothiol biochemistry has characteristics similar to those of glutathione but also has a variety of unique features. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/ s00203-002-0469-4. On that page (frame on the left side), a link takes you directly to the supplementary material.
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