Molybdenum cofactor synthesis 2
Available structures
PDB Ortholog search: RCSB
RNA expression pattern

Molybdenum cofactor synthesis protein 2A and molybdenum cofactor synthesis protein 2B are a pair of proteins that in humans are encoded from the same MOCS2 gene.[1][2][3] These two proteins dimerize to form molybdopterin synthase.


Eukaryotic molybdoenzymes use a unique molybdenum cofactor (MoCo) consisting of a pterin, termed molybdopterin, and the catalytically active metal molybdenum. MoCo is synthesized from precursor Z (now known as cyclic pyranopterin monophosphate) by the heterodimeric enzyme molybdopterin synthase.[3]


The large and small subunits of molybdopterin synthase are both encoded from the MOCS2 gene by overlapping open reading frames. The proteins were initially thought to be encoded from a bicistronic transcript. They are now thought to be encoded from monocistronic transcripts. Alternatively spliced transcripts have been found for this locus that encode the large and small subunits.[3]

The MOCS2 gene contains 7 exons. Exons 1 to 3 encode MOCS2A (the small subunit), and exons 3 to 7 encode MOCS2B (large subunit).[1]

Genetic disease

Defects in both copies of MOCS2 cause the molybdenum cofactor deficiency disease in babies.[4]

Protein Structure

MOCS2A and MOCS2B subunits form dimers in solution. These dimers in turn dimerize to form the tetrameric molybdopterin synthase complex.[5]


Further reading