BIO2 (YGR286C, P32451) notes

Identity

• Biotin synthase, mitochondrial (BioB), EC 2.8.1.6; radical SAM superfamily, biotin synthase family; predicted 16-residue mitochondrial transit peptide; binds a [4Fe-4S] (SAM-binding) and a [2Fe-2S] cluster by similarity [UniProt BIO2 entry, file genes/yeast/BIO2/BIO2-uniprot.txt].
• Catalyses the last step of biotin synthesis: dethiobiotin -> biotin (sulfur insertion) [UniProt "PATHWAY: Cofactor biosynthesis; biotin biosynthesis; biotin from 7,8-"].

Experimental evidence

• A transposon mutant blocked in the last step of biotin synthesis was disrupted in BIO2 PMID:10525840 (abstract only).
• Mitochondrial localization: GFP survey (Huh et al. 2003, PMID:14562095) and mitochondrial proteomics (PMID:24769239) (both abstract-only in cache; UniProt records mitochondrion from PMID:14562095).

Context

• S288C is a biotin auxotroph lacking the upstream BIO1/BIO6 pimeloyl branch; the yeast pathway was rebuilt by horizontal transfer and gene duplication (Hall & Dietrich 2007, PMID:18073433, from web search; not cached). BIO2 is still required for converting dethiobiotin to biotin.
• Mitochondrial biotin synthase is shared with plants (BIO2 in Arabidopsis mitochondria), consistent with Fe-S cluster supply from mitochondrial ISC machinery.