Parent Class:

EC-Numbers → 6 -- Ligases → 6.3 -- Forming carbon-nitrogen bonds → 6.3.1 -- Acid--ammonia (or amide) ligases (amide synthases)

Synonyms: MshC, MshC ligase, Cys:GlcN-Ins ligase, mycothiol ligase

Systematic Name: L-cysteine:1-O-(2-amino-2-deoxy-α-D-glucopyranosyl)-1D-myo-inositol ligase (AMP-forming)

Unification Links: BRENDA:6.3.1.13, ENZYME:6.3.1.13, IUBMB-ExplorEnz:6.3.1.13

Reaction:
1-(2-amino-2-deoxy-α-D-glucopyranosyl)-1D-myo-inositol + L-cysteine + ATP → deacetylmycothiol + AMP + diphosphate + H⁺

Enzymes and Genes:
L-cysteine : 1 D-myo-inositol 2-amino-2-deoxy-α-D-glucopyranoside ligase: mshC ( Mycolicibacterium smegmatis )

Summary:
This enzyme is a key enzyme in the biosynthesis of mycothiol, a small molecular weight thiol found in Mycobacteria spp. and other actinomycetes. Mycothiol plays a fundamental role in these organisms by helping to provide protection from the effects of reactive oxygen species and electrophiles, including many antibiotics. The enzyme may represent a novel target for new classes of antituberculars [GutierrezLugo06].

Citations: [Fan07, Tremblay08]

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References

Fan07: Fan F, Luxenburger A, Painter GF, Blanchard JS (2007). "Steady-state and pre-steady-state kinetic analysis of Mycobacterium smegmatis cysteine ligase (MshC)." Biochemistry 46(40);11421-9. PMID: 17848100

GutierrezLugo06: Gutierrez-Lugo MT, Newton GL, Fahey RC, Bewley CA (2006). "Cloning, expression and rapid purification of active recombinant mycothiol ligase as B1 immunoglobulin binding domain of streptococcal protein G, glutathione-S-transferase and maltose binding protein fusion proteins in Mycobacterium smegmatis." Protein Expr Purif 50(1);128-36. PMID: 16908186

Tremblay08: Tremblay LW, Fan F, Vetting MW, Blanchard JS (2008). "The 1.6 A crystal structure of Mycobacterium smegmatis MshC: the penultimate enzyme in the mycothiol biosynthetic pathway." Biochemistry 47(50);13326-35. PMID: 19053270

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Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 46(D1):D633-D639 2018
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