Amplification of the NADPH-Related Genes zwf and gnd for the Oddball Biosynthesis of PHB in an E. coli Transformant Harboring a Cloned phbCAB Operon

概要

論文の詳細を見る
NADPH, a major reducing power in microorganisms, is mostly generated from the pentose phosphate (PP) pathway by glucose-6-phosphate dehydrogenase (G6PDH) and 6-posphogluconate dehydrogenase (6PGDH) expressed by the zwf and gnd genes, respectively. The characteristics of these two genes in Escherichia coli were compared after their re-introduction into the parent strain for over-expression. zwf encoding G6PDH increased the level of NADPH 3 folds compared to gnd encoding 6PGDH. An excess of NADPH depressed cell growth mainly due to the inhibition of citrate synthase in the TCA cycle. Recombinant plasmids containing zwf or gnd co-integrated with the phbCAB operon from Raistonia eutropha were constructed, and introduced into E. coli for the oddball biosynthesis of PHB. The amount of PHB increased after enforcing the genes; especially the zwf gene an increase of around 41%, due to the rise in NADPH and the depressed TCA cycle, leading to the metabolic flux of intermediates to the pathway for the biosynthesis of PHB.
社団法人日本生物工学会の論文
2002-06-20