Molybdenum cofactor sulfurase, C-terminal (IPR005302)

Short name: MoCF_Sase_C

Overlapping homologous superfamilies


Domain relationships



Molybdenum cofactor (MOCO) sulphurases [PMID: 16784786] catalyse the insertion of a terminal sulphur ligand into the molybdenum cofactor, thereby converting the oxo form of MOCO to a sulphurylated form. Suphurylated MOCO is required by several enzymes, including: aldehyde oxidase (EC:, which function in the last step of abscisic acid biosynthesis in plants [PMID: 11549764]; and xanthine dehydrogenase (EC:, which synthesis uric acid from xanthine during nitrogen metabolism [PMID: 12650690].

This entry represents the beta-barrel C-terminal domain of MOCO sulphurase (MOSC domain), which has a beta-barrel structure similar to that of the beta-barrel domain in pyruvate kinase and contains a highly conserved cysteine residue required for activity. MOSC domains are found in several diverse metal-sulphur cluster biosynthesis proteins from both eukaryotes and prokaryotes. MOSC domains occu as either stand-alone forms, such as the YiiM protein from Escherichia coli, or fused to other domains, such as a NifS-like catalytic domain in MOCO sulphurase. The MOSC domain is predicted to be a sulphur-carrier domain that receives sulphur abstracted from pyridoxal phosphate-dependent NifS-like enzymes, on its conserved cysteine, and delivers it for the formation of diverse sulphur-metal clusters [PMID: 11886751].

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 and rhodanese superfamilies. Members of both these superfamilies, especially of the latter one, have been implicated in the synthesis of Fe-S clusters, through mobilisation of sulphur with their active cysteine.

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0003824 catalytic activity
GO:0030151 molybdenum ion binding
GO:0030170 pyridoxal phosphate binding

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE profiles