Biotin synthase/Biotin biosynthesis bifunctional protein BioAB (IPR002684)

Short name: Biotin_synth/BioAB

Overlapping homologous superfamilies

Family relationships

  • Biotin synthase/Biotin biosynthesis bifunctional protein BioAB (IPR002684)


This family consists of biotin synthase B-like and bifunctional biotin synthase AB proteins.

Biotin synthase EC: works with flavodoxin, S-adenosylmethionine, and possibly cysteine to catalyze the last step of the biotin biosynthetic pathway. The reaction consists of the introduction of a sulphur atom into dethiobiotin, thus requiring activation of C-H bonds [PMID: 8763940]. Biotin (vitamin H) is a prosthetic group in enzymes catalysing carboxylation and transcarboxylation reactions [PMID: 8917070].

Biotin synthase from Escherichia coli is a homodimer of 76 kDa, with each polypeptide chain carrying an oxygen-sensitive (4Fe-4S) cluster, probably ligated by three cysteines of a CXXXCXXC box conserved among all known BioB sequences and a fourth still not identified ligand. BioB displays a pyridoxal phosphate-dependent cysteine desulphurase activity, which allows mobilisation of the sulphur atom from free cysteine [PMID: 12119030].

GO terms

Biological Process

GO:0009102 biotin biosynthetic process

Molecular Function

GO:0004076 biotin synthase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

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