title: Construction of Escherichia coli strains producing L-serine from glucose.
abstract: L-Serine is usually produced from glycine. We have genetically engineered Escherichia coli to produce L-serine from glucose intracellularly. D-3-Phosphoglycerate dehydrogenase (PGDH, EC 1.1.1.95) in E. coli catalyzes the first committed step in L-serine formation but is inhibited by L-serine. To overcome this feedback inhibition, both the His(344) and Asn(346) residues of PGDH were converted to alanine and the mutated PGDH (PGDH(dr)) became insensitive to L-serine. However, overexpression of PGDH(dr) gave no significant increase of L-serine accumulation but, when L-serine deaminase genes (sdaA, sdaB and tdcG) were deleted, serine accumulated: (1) deletion of sdaA gave up to 0.03 mmol L-serine/g; (2) deletion of both sdaA and sdaB accumulated L-serine up to 0.09 mmol/g; and (3) deletion of sdaA, sdaB and tdcG gave up to 0.13 mmol L-serine/g cell dry wt.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, National Engineering Laboratory for Industrial Enzymes, College of Biotechnology, Tianjin University of Science & Technology, Tianjin, 300457, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.forename: Gu-Kui
authors.initials: GK
authors.lastname: Chen
authors.forename: Xin-Wei
authors.initials: XW
authors.lastname: Tong
authors.forename: Hui-Tu
authors.initials: HT
authors.lastname: Zhang
authors.forename: Xiao-Guang
authors.initials: XG
authors.lastname: Liu
authors.forename: Yi-Han
authors.initials: YH
authors.lastname: Liu
authors.forename: Fu-Ping
authors.initials: FP
authors.lastname: Lu
mesh_terms: D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000378:metabolism; D055786:Gene Knockout Techniques; D005818:Genetic Engineering / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D012695:L-Serine Dehydratase / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D050543:Phosphoglycerate Dehydrogenase / Q000378:metabolism; D012694:Serine / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D012694:Serine; D050543:Phosphoglycerate Dehydrogenase; D012695:L-Serine Dehydratase; D005947:Glucose