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 ¹⁴C-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.