Biotechnology Letters, Vol.37, No.5, 1063-1071, 2015
Comparative proteome analysis of global effect of POS5 and zwf-ppnK overexpression in L-isoleucine producing Corynebacterium glutamicum ssp lactofermentum
Corynebacterium glutamicum ssp. lactofermentum strain JHI3-156 produces l-isoleucine (Ile). Overexpression of the Saccharomyces cerevisiae-derived NADH kinase gene (POS5) and the endogenous glucose-6-phosphate dehydrogenase and NAD kinase genes (zwf-ppnK) in JHI3-156 increased Ile production by 26 and 31 %, respectively. To decipher the global effect of POS5 and zwf-ppnK overexpression on Ile biosynthesis, proteomic analysis was conducted. Twenty-four differentially expressed proteins were identified in the POS5-overexpressing strain, most of which are related to inositol catabolism, central carbon metabolism, anaplerotic pathway, protein biosynthesis and the stress response. In the zwf-ppnK-overexpressing strain, seven differentially-expressed proteins, including PpnK and anaplerotic enzymes, were identified. This result indicates the involvement of a novel inositol catabolism step and the importance of the anaplerotic pathway in Ile biosynthesis. This finding will be helpful in the systematic metabolic engineering of C. glutamicum for Ile biosynthesis.
Keywords:Anaplerotic pathway;Corynebacterium glutamicum ssp lactofermentum;Inositol catabolism;L-Isoleucine;Proteomic analysis