Analysis of cepA encoding an efflux pump-like protein in Corynebacterium glutamicum

• Published in: The journal of microbiology 2014, 52(4), , pp.278-283
• Main Authors: Sim, Soo-Yeon, Hong, Eun-Ji, Kim, Younhee, Lee, Heung-Shick
• Format: Article
• Language: English
• Subjects: Amino acids; ampicillin; antibiotic resistance; Antibiotics; Bacillus subtilis; Bacillus subtilis - genetics; Bioinformatics; Biological Transport, Active; Biomedical and Life Sciences; cell growth; Corynebacterium glutamicum; Corynebacterium glutamicum - genetics; Corynebacterium glutamicum - growth & development; Corynebacterium glutamicum - metabolism; E coli; Escherichia coli; Escherichia coli - genetics; Exports; Gene Deletion; Gene Expression; gene overexpression; Genes; Genetic engineering; Genomes; Genomics and Molecular Biology; Life Sciences; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Microbial Genetics; Microbiology; multiple drug resistance; mutants; nalidixic acid; nucleosides; Physiology; Plasmids; Proteins; Sequence Homology, Amino Acid; Toxic substances; transport proteins; 생물학
• ISSN: 1225-8873; 1976-3794
• DOI: 10.1007/s12275-014-3461-1

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.