PROSITE documentation PDOC51340

MOSC domain profile

The molybdenum cofactor (MOCO) sulfurase C-terminal (MOSC) domain is a conserved region of about 125-170 residues present in diverse metal-sulfur cluster biosynthesis proteins from both prokaryotes and eukaryotes. MOSC domains occur either as stand-alone forms such as the bacterial YiiM proteins, or fused to other domains such as a NifS-like catalytic domain in MOCO sulfurase. The MOSC domain is predicted to be a sulfur-carrier domain that receives sulfur abstracted by the pyridoxal phosphate-dependent NifS-like enzymes, on its conserved cysteine, and delivers it for the formation of diverse sulfur-metal clusters [1].

The MOSC domain contains several patches of hydrophobic residues and an absolutely conserved cysteine residue situated closer to the C-terminal end of the domain. The absolutely conserved cysteine in the MOSC domain is reminiscent of the analogous conservation of a cysteine in the active site of the thioredoxin (see <PDOC00172>) and rhodanese (see <PDOC00322>) superfamilies. Members of both these superfamilies, especially of the latter one, have been implicated in the synthesis of Fe-S clusters, through mobilization of sulfur with their active cysteine. The MOSC domain is predicted to adopt a β-strand-rich fold with a couple of isolated α-helical elements [1].

The profile we developed covers the entire MOSC domain.