| 论文题目: | Identification and Characterization of gamma-Aminobutyric Acid Uptake System GabP(Cg) (NCgl0464) in Corynebacterium glutamicum |
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| 作者: | Zhao, Z; Ding, JY; Ma, WH; Zhou, NY; Liu, SJ |
| 联系作者: | Liu, SJ |
| 刊物名称: | APPLIED AND ENVIRONMENTAL MICROBIOLOGY |
| 期: | 8 |
| 卷: | 78 |
| 页: | 2596-2601 |
| 年份: | 2012 |
| 影响因子: | 3.829 |
| 论文下载: | |
| 摘要: | Corynebacterium glutamicum is widely used for industrial production of various amino acids and vitamins, and there is growing interest in engineering this bacterium for more commercial bioproducts such as gamma-aminobutyric acid (GABA). In this study, a C. glutamicum GABA-specific transporter (GabP(Cg)) encoded by ncgl0464 was identified and characterized. GabP(Cg) plays a major role in GABA uptake and is essential to C. glutamicum growing on GABA. GABA uptake by GabP(Cg) was weakly competed by L-Asn and L-Gln and stimulated by sodium ion (Na+). The K-m and V-max values were determined to be 41.1 +/- 4.5 mu M and 36.8 +/- 2.6 nmol min(-1) (mg dry weight [DW])(-1), respectively, at pH 6.5 and 34.2 +/- 1.1 mu M and 67.3 +/- 1.0 nmol min(-1) (mg DW)(-1), respectively, at pH 7.5. GabP(Cg) has 29% amino acid sequence identity to a previously and functionally identified aromatic amino acid transporter (TyrP) of Escherichia coli but low identities to the currently known GABA transporters (17% and 15% to E. coli GabP and Bacillus subtilis GabP, respectively). The mutant RES167 Delta ncgl0464/pGXKZ9 with the GabP(Cg) deletion showed 12.5% higher productivity of GABA than RES167/pGXKZ9. It is concluded that GabP(Cg) represents a new type of GABA transporter and is potentially important for engineering GABA-producing C. glutamicum strains. |
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