title: A membrane transporter required for 3-hydroxybutyrate uptake during the early sporulation stage in Bacillus subtilis.
abstract: Exogenous 3-hydroxybutyrate can be utilized by a variety of soil bacteria as a carbon and energy source. However, the membrane transporter responsible for 3-hydroxybutyrate uptake remains unidentified. The Bacillus subtilis strain 168 gene yxjC (herein renamed hbuT) encodes a putative gluconate transporter GntT-type membrane transporter with a previously unknown function. hbuT is organized within the same operon with genes that are used for metabolism of 3-hydroxybutyrate. Here we report that a null mutation of hbuT reduced uptake of 3-hydroxybutyrate by B. subtilis cells grown in nutrient sporulation medium. The SigE-controlled HbuT transporter apparently plays a major role in the uptake of 3-hydroxybutyrate. Uptake of 3-hydroxybutyrate by the HbuT transporter occurred in a specific manner at the early sporulation stage. SigE-controlled hbuT expression and 3-hydroxybutyrate uptake were also subject to CcpA-mediated glucose repression. hbuT expression was not induced by exogenous 3-hydroxybutyrate and B. subtilis cells could not utilize 3-hydroxybutyrate as a sole carbon source for growth. HbuT homologs are present in a wide variety of Gram-positive Bacillus species, some Gram-negative Acinetobacter species and a small group of other bacteria. This is the first tentative identification of a membrane transporter responsible for the uptake of 3-hydroxybutyrate in bacteria.
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei 112, Taiwan, Republic of China.
authors.forename: Yueh-Chi
authors.initials: YC
authors.lastname: Shen
authors.affiliation: Institute of Biochemistry and Molecular Biology, School of Life Science, National Yang-Ming University, Taipei 112, Taiwan, Republic of China gcshaw@ym.edu.tw.
authors.forename: Gwo-Chyuan
authors.initials: GC
authors.lastname: Shaw
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D009154:Mutation; D009876:Operon; D012808:Sigma Factor / Q000235:genetics / Q000378:metabolism; D013171:Spores, Bacterial / Q000235:genetics / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; D012808:Sigma Factor; C111259:sigE protein, Bacteria; D002244:Carbon; D020155:3-Hydroxybutyric Acid
keywords: gene regulation; membrane transport; nutrient acquisition