The ncgl1108 ( PheP Cg ) gene encodes a new l -Phe transporter in Corynebacterium glutamicum

Corynebacterium glutamicum played a central role in the establishment of fermentative production of amino acids, and it is a model for genetic and physiological studies. The general aromatic amino acid transporter, AroP Cg , was the sole functionally identified aromatic amino acid transporter from C. glutamicum . In this study, the ncgl1108 (named as pheP Cg ), which is located upstream of the genetic cluster ( ncgl1110 ∼ ncgl1113 ) for resorcinol catabolism, was identified as a new l -Phe specific transporter from C. glutamicum RES167. The disruption of pheP Cg resulted in RES167∆ ncgl1108 , and this mutant showed decreased growth on l -Phe (as nitrogen source) but not on l -Tyr or l -Trp. Uptake assays with unlabeled and 14 C-labeled l -Phe and l -Tyr indicated that the mutants RES167∆ ncgl1108 showed significant reduction in l -Phe uptake than RES167. Expression of pheP Cg in RES167∆ ncgl1108 /pGXKZ1 or RES167∆( ncgl1108 - aroP Cg )/pGXKZ1 restored their ability to uptake for l -Phe and growth on l -Phe. The uptake of l -Phe was not inhibited by nine amino acids but by l -Tyr. The K m and V max values of RES167∆( ncgl1108-aroP Cg ) / pGXKZ1 for l -Phe were determined to be 10.4 ± 1.5 μM and 1.2 ± 0.1 nmol min −1 (mg DW) −1 , respectively, which are different from K m and V max values of RES167∆( ncgl1108-aroP Cg ) for l -Phe [4.0 ± 0.4 μM and 0.6 ± 0.1 nmol min −1 (mg DW) −1 ]. In conclusion, this PheP Cg is a new l -Phe transporter in C. glutamicum .