The Effect of Cyclic AMP on the Permeability Characteristics of the Escherichia coli Membrane System.

摘要

Various metabolic functions associated with the Escherichia coli membrane system were analyzed in mutant strains lacking adenylate cyclase (cya mutations) or cyclic AMP binding protein (CRP) activity (crp mutations). Mutations which have suppressed the organism's requirement for cyclic AMP were also studied, and mutants of Salmonella typhimurium were constructed which are cya or crp in addition to lacking the enzymes of the phosphoenolpyruvate: phosphotransferase system (PTS). These studies have established that key transport and bioenergetic activities of the enterobacterial membrane are regulated at the genetic level of transcription by the cAMP-CRP regulatory complex. The ability of E. coli to transport substrates via PTS and non-PTS routes are under this control. The organism's ability to generate a proton motive force (PMF) and to link this force to transport activities and ATP synthesis are also under this control. All parts of the E. coli envelope, the inner, cytoplasmic membrane, the periplasmic region, and the outer membrane are to one degree or another affected by the cAMP-CRP regulatory function. (Author)