Adenylyltransferase and sulfurtransferase MOCS3/Uba4 (IPR028885)

Short name: MOCS3/Uba4

Overlapping homologous superfamilies

Family relationships



This entry includes adenylyltransferase and sulfurtransferase MOCS3 and its homologue, Uba4, from yeasts.

In budding yeasts, Uba4 receives sulphur from Nfs1 and Tum1 [PMID: 21904977]. Uba4 then forms an acyl adenylate intermediate with the C-terminal of the Urm1 protein, and then forms an acyl disulfide bond between Uba4 Cys397 and the Urm1 C-terminal glycin [PMID: 21904977]. Subsequently, the activated Urm1 acts as a sulphur carrier in the process of eukaryotic transfer RNA (tRNA) thiolation [PMID: 19145231].

MOCS3 plays a central role in 2-thiolation of mcm5S2U at tRNA wobble positions of cytosolic tRNA(Lys), tRNA(Glu) and tRNA(Gln) [PMID: 19017811]. It is also essential during biosynthesis of the molybdenum cofactor [PMID: 15073332, PMID: 15910006]. MOCS3 acts by mediating the C-terminal thiocarboxylation of sulfur carriers Urm1 and MOCS2A (the small subunit of molybdopterin synthase) [PMID: 19145231, PMID: 19151091, PMID: 18491921, PMID: 22453920].

GO terms

Biological Process

GO:0002143 tRNA wobble position uridine thiolation

Molecular Function

GO:0004792 thiosulfate sulfurtransferase activity

Cellular Component

GO:0005829 cytosol

Contributing signatures

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