Overexpression of Key Enzymes in Arginine Biosynthetic Pathway and their Effects on L-arginine Production

Abstract:

Carbamoyl phosphate synthase, Acetyl ornithine amino transferase and ornithine acetyl transferase encoded by CarAB, ArgD and ArgJ were the key enzymes in L-arginine biosynthetic pathway. In Corynebacterium glutamicum ATCC14067, with the plasmids pEC- XK99E-p and PEC-T18mob2, the genes of CarAB, ArgD and ArgJ in the arginine biosynthetic pathway were expressed individually, ArgD and ArgJ were overexpressed in series and the CarAB, ArgD and ArgJ were co-expressed. The ability of producing L-arginine of the recombination strains, 14067-pEC-CarAB, 14067-T18-ArgD, 14067-T18-ArgJ, 14067-T18-ArgDJ and 14067-pEC-CarAB-T18-ArgDJ, increased 1.61, 1.14, 1.19, 1.28 and 2.19 times, respectively, in shake flask which compared with the starting strain ATCC14067. The real-time quantitative PCR showed that the relative expression of genes CarA, CarB, ArgD and ArgJ in strain 14067-pEC-CarAB-T18-ArgDJ were 2.50, 5.60, 3.59 and 4.70 times, respectively, than ATCC14067. Therefore, overexpression of CarAB, ArgD and ArgJ genes can effectively improve the production of L-arginine.