Effects of pyruvate kinase on the growth of Corynebacterium glutamicum and L-serine accumulation. (April 2017)

• Record Type: Journal Article
• Authors: Zhang, Xiaomei; Lai, Lianhe; Xu, Guoqiang; Zhang, Xiaojuan; Shi, Jinsong; Xu, Zhenghong
• Is Part Of: Process biochemistry. Volume 55(2017)
• Page Start: 32
• Page End: 40
• Publication Date: 2017-04
• Subjects: L-serine -- Pyruvate kinase -- Corynebacterium glutamicum -- Mutation -- Deletion; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2017.01.028
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: C. glutamicum SYPS-062 had mutation in the 308 residue (Met→Ile) compared with the model strain. Significantly lower PYK activity was found in C. glutamicum SYPS-062. This mutation site in the 308 residue closely associated with its activity. The lower activity of PYK can improve L-serine production. The pyk -deleted mutant did not affect the cell growth, and L-serine increased 12%. Abstract: Pyruvate kinase (PYK) is an important enzyme in the intermediary metabolism and has attracted much attention as a target for metabolic engineering of Corynebacterium glutamicum . Genome sequencing revealed that the 308 residue of PYK was mutated from methionine in model strain C. glutamicum ATCC14067 to isoleucine in L-serine-producing strain C. glutamicum SYPS-062. Consequently, a significantly lower PYK activity (77%) was noted in C. glutamicum SYPS-062, when compared with that in C. glutamicum ATCC14067. To confirm the role of this point mutation, pyk in both C. glutamicum SYPS-062 and C. glutamicum SYPS-062-33aΔSSAA was reversely mutated to restore the PYK enzyme activity, which led to a 33.1% and 28.8% decrease in L-serine titer, respectively. This is the first report to show that the (Met-308→Ile) mutation site of pyk is closely associated with its activity and apparently affected L-serine production. Furthermore, pyk was deleted in strain C. glutamicum SYPS-062-33aΔSSAA, and the resulting strain did not show alteration in growth rate and presented a 12% increase in L-serine production.