Mycothiol (MSH or AcCys-GlcN-Ins) is an unusual

thiol In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl gro ...

compound found in the

Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrestrial or aquatic. They are of great economic importance to humans because agriculture and forests depend on their contributions to soi ...

. It is composed of a

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, sometime ...

residue with an acetylated amino group linked to

glucosamine Glucosamine (C6H13NO5) is an amino sugar and a prominent precursor in the biochemical synthesis of glycosylated proteins and lipids. Glucosamine is part of the structure of two polysaccharides, chitosan and chitin. Glucosamine is one of the most ...

, which is then linked to

inositol Inositol, or more precisely ''myo''-inositol, is a carbocyclic sugar that is abundant in the brain and other mammalian tissues; it mediates cell signal transduction in response to a variety of hormones, neurotransmitters, and growth factors and ...

. The oxidized,

disulfide In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In ...

form of mycothiol (MSSM) is called mycothione, and is reduced to mycothiol by the

flavoprotein Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin. Flavoproteins are involved in a wide array of biological processes, including removal of radicals contributing to oxidative stress, photosynthesis, and DNA repair ...

mycothione reductase In enzymology, a mycothione reductase () is an enzyme that catalyzes the chemical reaction :mycothione + NAD(P)H + H + \rightleftharpoons 2 mycothiol + NADP+ in ''M. tuberculosis'' and other actinomycetes. The 2 substrates of this enzyme are m ...

. Mycothiol biosynthesis and mycothiol-dependent enzymes such as

mycothiol-dependent formaldehyde dehydrogenase In enzymology, a mycothiol-dependent formaldehyde dehydrogenase () is an enzyme that catalyzes the chemical reaction :formaldehyde + mycothiol + NAD+ \rightleftharpoons S-formylmycothiol + NADH + 2 H+ The 3 substrates of this enzyme are formald ...

and mycothione reductase have been proposed to be good

drug target A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets ...

s for the development of treatments for

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...

References

{{reflist Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction Published 21 May 2013. Nature Communications4, Article number:1881 doi:10.1038/ncomms2898

External links

The Biochemistry of Pathogens: The metabolism and function of mycothiol in the mycobacteria.
Thiols Acetamides Propionamides Tetrahydropyrans

See also

References

External links