title: Analysis of cepA encoding an efflux pump-like protein in Corynebacterium glutamicum.
abstract: A gene encoding a homolog of purine efflux proteins of Escherichia coli and Bacillus subtilis was identified in the genome of Corynebacterium glutamicum and designated as cepA. The gene encoded a putative protein product, containing 12 transmembrane helixes, which is a typical feature of integral membrane transport proteins. To elucidate the function of the gene, we constructed a cepA deletion mutant (ΔcepA) and a cepA-overexpressing strain and analyzed their physiological characteristics. The cepA gene could be deleted with no critical effect on cell growth. However, the cell yield of a ΔcepA strain was decreased by 10% as compared to that of a strain carrying a cepA-overexpression plasmid (P180-cepA). Further analysis identified increased resistance of the P180-cepA strain to the purine analogues 6-mercaptopurine and 6-mercaptoguanine, but not to 2-aminopurine and purine nucleoside analogues. Moreover, this strain showed increased resistance to the antibiotics nalidixic acid and ampicillin. Collectively, these data suggest that cepA is a novel multidrug resistance gene and probably functions in the efflux of toxic substances from the inside of cells to the environment, thus allowing cells to reach a higher cell yield.
authors.affiliation: Department of Biotechnology and Bioinformatics, Korea University, Sejong, 339-700, Republic of Korea.
authors.forename: Soo-Yeon
authors.initials: SY
authors.lastname: Sim
authors.forename: Eun-Ji
authors.initials: EJ
authors.lastname: Hong
authors.forename: Younhee
authors.initials: Y
authors.lastname: Kim
authors.forename: Heung-Shick
authors.initials: HS
authors.lastname: Lee
mesh_terms: D001412:Bacillus subtilis / Q000235:genetics; D001693:Biological Transport, Active; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D017353:Gene Deletion; D015870:Gene Expression; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D026901:Membrane Transport Proteins