Expression and Functional Identification of arpA in E. coli

Article Abstract: The gene arpA in E. coli lies between aceK gene encoding isocitrate dehydrogenase kinase and iclR gene encoding isocitrate lyase regulator. The coding sequence of arpA gene is amplified using PCR with primers designed according to the genomic sequence of E. coli. The PCR product is cloned into pET-28b （＋）. ArpA protein is overexpressed in E. coli Rosetta （DE3） under IPTG induction. The arpA gene is knocked out via chromosomal homologous recombination in E. coli, creating the deletion strain△arpAMG1655. During growth on glucose medium, the growth rate of AarpA-MG1655 is closed to that of the wild type E. coli MG1655. The former is 95% of the latter. The growth rate of AarpA-MG1655 is almost the same as that of E. coli MG1655 during growth on acetate medium, indicating that ArpA has no apparent effect on E. coli and can not be the regulator of Acyl-CoA Synthetase（Acs）. ArpA contains the ankyrin repeat （ANK） and is highly homologous with many proteins which contain ANK. The analysis of phylogeny implies that ANK-like proteins in some virus and bacteria can be the result of horizontal gene transfer in evolution.