title: Enhancing human-like collagen accumulation by deleting the major glucose transporter ptsG in recombinant Escherichia coli BL21.
abstract: Collagen has been proven to be a valuable biomedical material for many medical applications. Human-like collagen (HLC) is a novel important biomedical material with diverse medical applications. In this work, recombinant Escherichia coli BL21 3.7 ∆ptsG was constructed, the characters of ptsG mutant strain were analyzed, and real-time quantitative polymerase chain reaction (PCR) was applied to investigate the effect of ptsG gene deletion on the transcriptional level of the phosphotransferase system (PTS) genes responsible for glucose transport. The HLC production and cell growth ability were 1.33- and 1.24-fold higher than those of its parent strain in the fermentation medium, respectively, and 1.16- and 1.17-fold in the modified minimal medium individually. The acetate accumulation decreased by 42%-56% compared to its parent strain in the fermentation medium, and 70%-87% in the modified minimal medium. The results of RT-qPCR showed that the transcriptional level of crr, ptsH, ptsI, and blgF in ptsG mutant all decreased dramatically, which inferred a decrease in the glucose uptake rate, but the transcriptional level of FruB and manX increased slightly, which demonstrated the activation of fructose- and mannose-specific transport pathways in the ptsG mutant. This study demonstrates that ptsG deletion is an effective strategy to reduce acetate accumulation and increase biomass and HLC production.
authors.affiliation: Shaanxi R&D Center of Biomaterial and Fermentation Engineering, School of Chemical Engineering, Northwest University, Xi'an, People's Republic of China; Shaanxi Key Laboratory of Degradable Biomedical Materials, School of Chemical Engineering, Northwest University, Xi'an, People's Republic of China.
authors.forename: Yan'e
authors.initials: Y
authors.lastname: Luo
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Daidi
authors.initials: D
authors.lastname: Fan
authors.forename: Tingzhen
authors.initials: T
authors.lastname: Mu
authors.forename: Wenjiao
authors.initials: W
authors.lastname: Xue
authors.forename: Junfeng
authors.initials: J
authors.lastname: Hui
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Ma
mesh_terms: D003094:Collagen / Q000096:biosynthesis* / Q000737:chemistry / Q000627:therapeutic use; D004926:Escherichia coli; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D003094:Collagen; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C031629:phosphoenolpyruvate-glucose phosphotransferase; D005947:Glucose
keywords: RT-qPCR; acetate accumulation; glucose uptake; human-like collagen; ptsG gene deletion