title: A versatile Escherichia coli strain for identification of biotin transporters and for biotin quantification.
abstract: Biotin is an essential cofactor of carboxylase enzymes in all kingdoms of life. The vitamin is produced by many prokaryotes, certain fungi, and plants. Animals depend on biotin uptake from their diet and in humans lack of the vitamin is associated with serious disorders. Many aspects of biotin metabolism, uptake, and intracellular transport remain to be elucidated. In order to characterize the activity of novel biotin transporters by a sensitive assay, an Escherichia coli strain lacking both biotin synthesis and its endogenous high-affinity biotin importer was constructed. This strain requires artificially high biotin concentrations for growth. When only trace levels of biotin are available, it is viable only if equipped with a heterologous high-affinity biotin transporter. This feature was used to ascribe transport activity to members of the BioY protein family in previous work. Here we show that this strain together with its parent is also useful as a diagnostic tool for wide-concentration-range bioassays.
authors.affiliation: Institut für Biologie/Mikrobiologie; Humboldt-Universität zu Berlin; Berlin, Germany.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Finkenwirth
authors.affiliation: Institut für Biologie/Mikrobiologie; Humboldt-Universität zu Berlin; Berlin, Germany.
authors.forename: Franziska
authors.initials: F
authors.lastname: Kirsch
authors.affiliation: Institut für Biologie/Mikrobiologie; Humboldt-Universität zu Berlin; Berlin, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Eitinger
mesh_terms: D001681:Biological Assay / Q000379:methods*; D001710:Biotin / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics*; D015202:Protein Engineering / Q000379:methods; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D027981:Symporters / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology*
chemical_list: D011994:Recombinant Proteins; D027981:Symporters; C119981:biotin transporter; D001710:Biotin
keywords: ABC transporter; BioY; ECF transporter; biotin bioassay; vitamins