Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile C...Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile CRISPR-Cas9 based anti-phage system for bacteriophages defense in E.coli.Two conjugative plasmids pGM1(phosphoglucomutase 1)and pGM2 carrying one and two guide RNAs,respectively,were designed to defend against a filamentous phage.The results showed that the pGM1 and pGM2 could decrease the phage infection rate to 1.6%and 0.2%respectively in infected cells.For preventing phage infection in E.coli,the pGM2 decreased the phage infection rate to 0.1%,while pGM1 failed to block phage infection.Sequence verification revealed that point mutations in protospacer or protospacer adjacent motif sequences of the phage genome caused loss of the defense function.These results support the potential application of MCBAS in E.coli cell factories to defend against phage infections.展开更多
Recently we constructed a murine IgE phage surfacedisplay library and screened out two IgE (Fab) cloneswith specific binding activity to Trichosanthin (TCS). Inthis work, the Vε and Vκ genes of the two clones werese...Recently we constructed a murine IgE phage surfacedisplay library and screened out two IgE (Fab) cloneswith specific binding activity to Trichosanthin (TCS). Inthis work, the Vε and Vκ genes of the two clones weresequenced and their putative germline gene usages werestudied. On the basis of the known 3D structure of Trichosanthin and antibody, molecular modeling was carriedout to study the antigen-antibody interaction. The possible antigenic determinant sites on the surface of TCSrecognized by both the clones were analyzed, and the reaction forces between TCS and two Fab fragments werealso analyzed respectively.展开更多
基金support from the National Key Research and Development Program of China(Grant No.2019YFA0903800)the National Natural Science Foundation of China(Grant Nos.31800719,21621004)the International(regional)cooperation and exchange projects(Grant No.31861143017).
文摘Escherichia coli is one of the most important microbial cell factories,but infection by bacteriophages in the environment may have a huge impact on its application in industrial production.Here,we developed a mobile CRISPR-Cas9 based anti-phage system for bacteriophages defense in E.coli.Two conjugative plasmids pGM1(phosphoglucomutase 1)and pGM2 carrying one and two guide RNAs,respectively,were designed to defend against a filamentous phage.The results showed that the pGM1 and pGM2 could decrease the phage infection rate to 1.6%and 0.2%respectively in infected cells.For preventing phage infection in E.coli,the pGM2 decreased the phage infection rate to 0.1%,while pGM1 failed to block phage infection.Sequence verification revealed that point mutations in protospacer or protospacer adjacent motif sequences of the phage genome caused loss of the defense function.These results support the potential application of MCBAS in E.coli cell factories to defend against phage infections.
文摘Recently we constructed a murine IgE phage surfacedisplay library and screened out two IgE (Fab) cloneswith specific binding activity to Trichosanthin (TCS). Inthis work, the Vε and Vκ genes of the two clones weresequenced and their putative germline gene usages werestudied. On the basis of the known 3D structure of Trichosanthin and antibody, molecular modeling was carriedout to study the antigen-antibody interaction. The possible antigenic determinant sites on the surface of TCSrecognized by both the clones were analyzed, and the reaction forces between TCS and two Fab fragments werealso analyzed respectively.
