Mycothiol

Mycothiol (MSH or AcCys-GlcN-Ins) is an unusual thiol compound found in the Actinobacteria.[1][2] It is composed of a cysteine residue with an acetylated amino group linked to glucosamine, which is then linked to inositol.[3] The oxidized, disulfide form of mycothiol (MSSM) is called mycothione, and is reduced to mycothiol by the flavoprotein mycothione reductase.[4][5] Mycothiol biosynthesis and mycothiol-dependent enzymes such as mycothiol-dependent formaldehyde dehydrogenase and mycothione reductase have been proposed to be good drug targets for the development of treatments for tuberculosis.[6][7]

Mycothiol

Names
IUPAC name (2R)-2-acetamido-N-[(2R,3R,4R,5S,6R)-4,5-dihydroxy-6-(hydroxymethyl)-2-[(2R,3S,5R,6R)-2,3,4,5,6-pentahydroxycyclohexyl]oxyoxan-3-yl]-3-sulfanylpropanamide
Other names Mycothiol
Identifiers
CAS Number	192126-76-4
3D model (JSmol)	Interactive image
ChEBI	CHEBI:16768
ChemSpider	10193006
KEGG	C06717
PubChem CID	441148
InChI InChI=1S/C17H30N2O12S/c1-4(21)18-5(3-32)16(29)19-7-9(23)8(22)6(2-20)30-17(7)31-15-13(27)11(25)10(24)12(26)14(15)28/h5-15,17,20,22-28,32H,2-3H2,1H3,(H,18,21)(H,19,29)/t5-,6+,7+,8+,9+,10-,11-,12+,13+,14+,15-,17+/m0/s1 Key: MQBCDKMPXVYCGO-FQBKTPCVSA-N InChI=1/C17H30N2O12S/c1-4(21)18-5(3-32)16(29)19-7-9(23)8(22)6(2-20)30-17(7)31-15-13(27)11(25)10(24)12(26)14(15)28/h5-15,17,20,22-28,32H,2-3H2,1H3,(H,18,21)(H,19,29)/t5-,6+,7+,8+,9+,10-,11-,12+,13+,14+,15-,17+/m0/s1 Key: MQBCDKMPXVYCGO-FQBKTPCVBG
SMILES CC(=O)N[C@@H](CS)C(=O)N[C@@H]1[C@H]([C@@H]([C@H](O[C@@H]1O[C@@H]2[C@@H]([C@@H]([C@H]([C@@H]([C@H]2O)O)O)O)O)CO)O)O
Properties
Chemical formula	C17H30N2O12S
Molar mass	486.49 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

See also

• Glutathione, analogous function in other Bacteria
• Bacillithiol

References

1. Fahey RC (2001). "Novel thiols of prokaryotes". Annu. Rev. Microbiol. 55: 333–56. doi:10.1146/annurev.micro.55.1.333. PMID 11544359.
2. Jothivasan VK, Hamilton CJ, (2008) Mycothiol: synthesis, biosynthesis and biological functions of the major low molecular weight thiol in actinomycetes. Natural Product Reports, (25). 1091-1117
3. Newton GL, Buchmeier N, Fahey RC (September 2008). "Biosynthesis and functions of mycothiol, the unique protective thiol of Actinobacteria". Microbiol. Mol. Biol. Rev. 72 (3): 471–94. doi:10.1128/MMBR.00008-08. PMC 2546866. PMID 18772286.
4. Patel MP, Blanchard JS (September 1999). "Expression, purification, and characterization of Mycobacterium tuberculosis mycothione reductase". Biochemistry. 38 (36): 11827–33. doi:10.1021/bi991025h. PMID 10512639.
5. Patel MP, Blanchard JS (May 2001). "Mycobacterium tuberculosis mycothione reductase: pH dependence of the kinetic parameters and kinetic isotope effects". Biochemistry. 40 (17): 5119–26. doi:10.1021/bi0029144. PMID 11318633.
6. Rawat M, Av-Gay Y (April 2007). "Mycothiol-dependent proteins in actinomycetes". FEMS Microbiol. Rev. 31 (3): 278–92. doi:10.1111/j.1574-6976.2006.00062.x. PMID 17286835.
7. Newton GL, Fahey RC (December 2002). "Mycothiol biochemistry". Arch. Microbiol. 178 (6): 388–94. doi:10.1007/s00203-002-0469-4. PMID 12420157.

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.