1. Identification and Characterization of γ-Aminobutyric Acid Uptake System GabP Cg (NCgl0464) in Corynebacterium glutamicum
- Author
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Jiu-Yuan Ding, Shuang-Jiang Liu, Wenhua Ma, Ning-Yi Zhou, and Zhi Zhao
- Subjects
Physiology ,Bacillus subtilis ,medicine.disease_cause ,Applied Microbiology and Biotechnology ,Aminobutyric acid ,gamma-Aminobutyric acid ,Corynebacterium glutamicum ,Escherichia coli ,medicine ,GABA transporter ,Peptide sequence ,gamma-Aminobutyric Acid ,chemistry.chemical_classification ,Sequence Homology, Amino Acid ,Ecology ,biology ,Membrane Transport Proteins ,Biological Transport ,Hydrogen-Ion Concentration ,biology.organism_classification ,Amino acid ,Kinetics ,chemistry ,Biochemistry ,biology.protein ,Gene Deletion ,Food Science ,Biotechnology ,medicine.drug - Abstract
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 γ-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 μM and 36.8 ± 2.6 nmol min −1 (mg dry weight [DW]) −1 , respectively, at pH 6.5 and 34.2 ± 1.1 μM 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 Δ 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.
- Published
- 2012