InterPro domain: IPR016155

This entry represents a structural domain with a beta-Grasp fold that is found in molybdopterinsynthase subunit MoaD [ 1 ], as well as in the thiamin biosynthesis sulphur carrier protein ThiS [ 2 ].

ThiS (thiaminS) is a 66 aa protein involved in sulphur transfer. ThiS is coded in the thiCEFSGH operon in Escherichia coli. ThiS proteins have two conserved Glycines at the COOH terminus. Thiocarboxylate is formed at the last G in the activation process. Sulphur is transferred from ThiI to ThiS in a reaction catalysed by IscS [ 3 ]. MoaD, a protein involved in sulphur transfer during molybdopterin synthesis, is about the same length and shows limited sequence similarity to ThiS. Both have the conserved GG at the COOH end.

1. Crystal structure of molybdopterin synthase and its evolutionary relationship to ubiquitin activation. Nat. Struct. Biol. 8, 42-6
2. Structure of the Escherichia coli ThiS-ThiF complex, a key component of the sulfur transfer system in thiamin biosynthesis. Biochemistry 45, 11-9
3. The iscS gene in Escherichia coli is required for the biosynthesis of 4-thiouridine, thiamin, and NAD. J. Biol. Chem. 275, 20096-103