title: Expression of the biotin biosynthetic operon of Escherichia coli is regulated by the rate of protein biotination.
abstract: In Escherichia coli biotin biosynthesis is repressed by high concentrations of exogenous biotin. This paper reports that upon high level production of the apo form of a biotinated protein, biotin operon expression was derepressed by 8-10-fold. The biotinated protein studied was the 1.3 S subunit of Propionibacterium shermanii, and transcarboxylase derepression was assayed by beta-galactosidase production in strains which carry a lacZ gene altered such that it is transcribed from biotin operon promoters. Depression of beta-galactosidase synthesis upon production of the apo 1.3 S protein was observed over a several hundred-fold range of biotin concentrations and also resulted in an increased level of biotin operon expression at maximally repressing biotin concentrations. Biotin operon derepression by apobiotin protein production seems a direct consequence of the properties of the biotin repressor protein which also functions as the ligase catalyzing the covalent attachment of biotin to apoproteins.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D001710:Biotin / Q000096:biosynthesis* / Q000378:metabolism / Q000494:pharmacology; D004794:Enzyme Repression; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D005786:Gene Expression Regulation; D005796:Genes; D005798:Genes, Bacterial; D009876:Operon; D010957:Plasmids; D011485:Protein Binding; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D001710:Biotin; D001616:beta-Galactosidase