THE GENE FOR BIOTIN SYNTHASE FROM SACCHAROMYCES-CEREVISIAE - CLONING,SEQUENCING, AND COMPLEMENTATION OF ESCHERICHIA-COLI STRAINS LACKING BIOTIN SYNTHASE

Biotin synthase catalyzes the insertion of a sulfur atom between two c arbon atoms of dethiobiotin to form biotin in the last step of the bio tin biosynthesis pathway. In Escherichia coli, biotin synthase is code d for by bioB gene. We report here cloning, sequencing, and initial fu nctional characterization of the yeast gene for biotin synthase in Sac charomyces cerevisiae. We have named this gene BIO2. It consists of a 355-codon open reading frame near the ZUO1 gene. Analysis of the yeast protein encoded by the BIO2 gene reveals that it shares extensive hom ology with biotin synthases of E. coli and Bacillus sphaericus. The ye ast and the two bacterial biotin synthase proteins have similar molecu lar weights, amino acid compositions, and hydropathies. The plasmid pU CBIO2 containing the yeast BIO2 gene completely complements E. coli bi oB(-) and Delta bio mutants and enables these mutants to grow on dethi obiotin. Although BIO2 is physically linked to ZUO1, which encodes the putative left-handed Z-DNA binding protein zuotin, it appears to be r egulated independently from it. The yeast BIO2 and ZUO1 genes reside n ear ADE3 gene on chromosome VII. BIO2 is the first eukaryotic gene rep orted from the biotin biosynthetic pathway. (C) 1994 Academic Press,In c.