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Literature summary for 2.3.1.189 extracted from

  • Newton, G.L.
    Ta, P.; Fahey, R.C.: A mycothiol synthase mutant of Mycobacterium smegmatis produces novel thiols and has an altered thiol redox status (2005), J. Bacteriol., 187, 7309-7316.
    View publication on PubMedView publication on EuropePMC
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Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
desacetylmycothiol + acetyl-CoA Mycobacterium tuberculosis
-
 mycothiol + coenzyme-A
-
 ?

Organism

Organism UniProt Comment Textmining
Mycobacterium tuberculosis
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
desacetylmycothiol + acetyl-CoA
-
 Mycobacterium tuberculosis mycothiol + coenzyme-A
-
 ?

General Information

General Information Comment Organism
malfunction the mycothiol synthase mutant mshD::Tn5, produces high levels of Cys-GlcN-Ins along with two novel thiols, N-formyl-Cys-GlcN-Ins and N-succinyl-Cys-GlcN-Ins, and a small amount of mycothiol. The nonenzymatic reaction of acyl-coenzyme A with Cys-GlcN-Ins to produce acyl-Cys-GlcN-Ins is a facile reaction under physiologic conditions, with succinyl-CoA being an order of magnitude more reactive than acetyl-CoA. The uncatalyzed reaction rates are adequate to account for the observed production of N-succinyl-Cys-GlcN-Ins and mycothiol under physiologic conditions. The N-acyl-Cys-GlcN-Ins compounds are maintained in a substantially reduced state in the mutant but that Cys-GlcN-Ins exists in disulfide forms at 5 to 40% at different stages of growth. Mycothiol is able to facilitate reduction of N-succinyl-Cys-GlcN-Ins disulfide through thiol-disulfide exchange, but N-formyl-Cys-GlcN-Ins is ineffective. The oxidized state of Cys-GlcN-Ins in cells appears to result from a high susceptibility to autoxidation and a low capacity of the cell to reduce its disulfide forms. The mutant exhibits no enhanced sensitivity to hydrogen peroxide, tert-butyl hydroperoxide, or cumene hydroperoxide relative to the parent strain, suggesting that the most abundant thiol, N-formyl-Cys-GlcN-Ins, functions as a substitute for mycothiol Mycobacterium tuberculosis