| Type: | Family | Name: | Biotin synthase/Biotin biosynthesis bifunctional protein BioAB |
| Description: | This family consists of biotin synthase B-like and bifunctional biotin synthase AB proteins. Biotin synthase 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 []. Biotin (vitamin H) is a prosthetic group in enzymes catalysing carboxylation and transcarboxylation reactions [].Biotin synthase from Escherichia coliis 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 sequencesand 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 []. | Short Name: | Biotin_synth/BioAB |
