MOCS3

Description

The MOCS3 (molybdenum cofactor synthesis 3) is a protein-coding gene located on chromosome 20.

MOCS3 (Molybdenum Cofactor Synthesis Protein 3) is an enzyme encoded by the MOCS3 gene in humans. It functions as both an adenylyltransferase and a sulfurtransferase. Molybdenum cofactor (MoCo) is crucial for the activity of all molybdoenzymes. MOCS3 is involved in the biosynthesis of MoCo, specifically by activating molybdopterin synthase (MPT synthase, encoded by MOCS2). The MOCS3 gene lacks introns and has a pseudogene located on chromosome 14.

MOCS3 plays a crucial role in the 2-thiolation of mcm(5)S(2)U at tRNA wobble positions within cytosolic tRNA(Lys), tRNA(Glu), and tRNA(Gln). This enzyme is also essential for the biosynthesis of molybdenum cofactor. MOCS3 facilitates the C-terminal thiocarboxylation of sulfur carriers URM1 and MOCS2A. Its N-terminus activates URM1 and MOCS2A as acyl-adenylates (-COAMP), followed by the transfer of persulfide sulfur from its catalytic cysteine to URM1 and MOCS2A, forming thiocarboxylation (-COSH) at their C-terminus. The reaction likely involves hydrogen sulfide generated from the persulfide intermediate, which acts as a nucleophile towards URM1 and MOCS2A, ultimately forming a transient disulfide bond. Notably, MOCS3 does not utilize thiosulfate as a sulfur donor; instead, NFS1 serves as the sulfur donor for thiocarboxylation reactions. MOCS3 interacts with NFS1.

MOCS3 is also known as UBA4.

Associated Diseases

WES Whole Exome Sequencing