A Canonical Biotin Synthesis Enzyme, 8-Amino-7-Oxononanoate Synthase (BioF), Utilizes Different Acyl Chain Donors in Bacillus subtilis and Escherichia coli
ABSTRACTBioF (8-amino-7-oxononanoate synthase) is a strictly conserved enzyme that catalyzes the first step in assembly of the fused heterocyclic rings of biotin. The BioF acyl chain donor has long been thought to be pimeloyl-CoA. Indeed,in vitrotheEscherichia coliandBacillus sphaericusenzymes have been shown to condense pimeloyl-CoA withl-alanine in a pyridoxal 5′-phosphate-dependent reaction with concomitant CoA release and decarboxylation ofl-alanine. However, recentin vivostudies ofE. coliandBacillus subtilissuggested that the BioF proteins of the two bacteria could have different specificities for pimelate thioesters in thatE. coliBioF may utilize either pimeloyl coenzyme A (CoA) or the pimelate thioester of the acyl carrier protein (ACP) of fatty acid synthesis. In contrast,B. subtilisBioF seemed likely to be specific for pimeloyl-CoA and unable to utilize pimeloyl-ACP. We now report genetic andin vitrodata demonstrating thatB. subtilisBioF specifically utilizes pimeloyl-CoA.IMPORTANCEBiotin is an essential vitamin required by mammals and birds because, unlike bacteria, plants, and some fungi, these organisms cannot make biotin. Currently, the biotin included in vitamin tablets and animal feeds is made by chemical synthesis. This is partly because the biosynthetic pathways in bacteria are incompletely understood. This paper defines an enzyme of theBacillus subtilispathway and shows that it differs from that ofEscherichia coliin the ability to utilize specific precursors. These bacteria have been used in biotin production and these data may aid in making biotin produced by biotechnology commercially competitive with that produced by chemical synthesis.