Enhancement of cytidine production by coexpression of gnd, zwf, and prs genes in recombinant Escherichia coli CYT15.
Cytidine is a precursor of several antiviral drugs. The pentose phosphate pathway (PPP) is primarily responsible for NADPH and 5-phospho-α-D-ribose 1-diphosphate as an important precursor of cytidine biosynthesis in Escherichia coli. To enhance cytidine production, we obtained the recombinant E. coli CYT15-gnd-prs-zwf that co-expressed the prs, zwf, and gnd genes encoding phosphoribosylpyrophosphate synthetase, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase (three key enzymes in PPP) respectively. In fermentation experiments, strain CYT15-gnd-prs-zwf produced 735 mg cytidine/l using glucose as substrate, which was approx. 128 % higher than the cytidine production by the parental strain (CYT15). Co-expression of zwf, gnd, and prs decreased growth (3.2 %) slightly and increased glucose uptake (72 %). This is the first study to report increased cytidine production by increasing metabolic flux through the PPP in E. coli.
Metabolic Engineering Laboratory, College of Biotechnology, Tianjin University of Science & Technology, No. 29 13 Main Street, Tianjin Economic and Technological Development Zone, Tianjin, China. fanght@nxu.edu.cn
Haitian
H
Fang
Xixian
X
Xie
Qingyang
Q
Xu
Chenglin
C
Zhang
Ning
N
Chen
D003562:Cytidine / Q000096:biosynthesis*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways / Q000235:genetics*; D010734:Phosphogluconate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012268:Ribose-Phosphate Pyrophosphokinase / Q000235:genetics / Q000378:metabolism
D011994:Recombinant Proteins; D003562:Cytidine; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D012268:Ribose-Phosphate Pyrophosphokinase