title: The role of ARGR repressor regulation on L-arginine production in Corynebacterium crenatum.
abstract: Corynebacterium crenatum SYA is an aerobic, Gram-positive, non-sporulating coryneform bacterium, and the mutant C. crenatum strain SYPA 5-5 can produce 30 g/l L-arginine under optimal culture conditions. In this study, the evolution of the cluster argCJBDFRGH (argC~H) involved in arginine biosynthesis in C. crenatum SYA, and SYPA 5-5 was investigated. Compared to the argR of its wild type C. crenatum SYA, a nucleotide substitution (C→T) within the argR gene of the mutant C. crenatum strain SYPA 5-5 was found. The inactivation of ARGR resulted in increased enzyme activities involved in L-arginine biosynthesis and increased L-arginine production in C. crenatum. In contrast, constructing an overexpressing argR C. crenatum/pTR, a complete and functional ARGR decreased the expression of enzymes, depressed transcriptional level of the argC~H cluster, and reduced the production of L-arginine in C. crenatum. It was thus evident that the inactivation of an ARGR suppressor could relieve a bottleneck in downstream steps of the L-arginine biosynthetic pathway, providing a good strategy for improving L-arginine production.
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, People's Republic of China.
authors.forename: Meijuan
authors.initials: M
authors.lastname: Xu
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Rao
authors.forename: Wenfang
authors.initials: W
authors.lastname: Dou
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Xu
mesh_terms: D001120:Arginine / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000502:physiology*; D003352:Corynebacterium / Q000201:enzymology; D015964:Gene Expression Regulation, Bacterial; D012097:Repressor Proteins / Q000502:physiology*
chemical_list: C087018:ArgR protein, Bacteria; D001426:Bacterial Proteins; D012097:Repressor Proteins; D001120:Arginine