Proteomic Analysis of a Response to Long-Chain Fatty Acid in Escherichia coli and Its Application

A long-chain fatty acid is a regulatory signal that modulates gene expression. In this study, proteomic studies that compared global translational differences between Escherichia coli cells grown in the presence of exogenous glucose and oleic acid were examined by two-dimensional gel electrophoresis (2-DE) and tandem mass spectrometry (LC-MS/MS). Of about 40 proteins showing altered expression levels with the presence of oleic acid, 10 including AldA, AceA, FadA, FadB, FadL, MalE, RbsB, Udp, Cdd and YccU were newly synthesized. Among them, the promoter of aldehyde dehydrogenase A (aldA promoter) was used for the production of a recombinant protein. Analysis of fluorescence intensities and confocal microscopic imaging revealed that aldA promoter is a very good promoter in that it is tightly controlled and highly expressed with active form compared with IPTG- inducible promoter. Thus the aldA promoter induced by oleic acid may be useful for achieving high-level expression of genes in E. coli.