Regulation of Porin-Mediated Outer Membrane Permeability by Nutrient Limitation in Escherichia coli

摘要: OmpF and OmpC porins were differentially regulated by nutrient limitation growth rate in glucose- or nitrogen-limited chemostat cultures of Escherichia coli. Transcriptional translational ompF fusions showed a sharp peak expression under glucose at D = 0.3 h−1, with lower amounts higher rates. The OmpR-dependent transcriptional stimulation minimal salts media was about 20-fold above excess levels 3-fold than that achieved low osmolarity. Analysis outer membrane protein results competition experiments porin mutants consistent the enhanced role limitation, but not N limitation. In contrast, major increasingly expressed very rates approaching starvation, when downregulated. summary, permeability N-limited, sugar-rich conditions is largely based on OmpC, whereas activity complex, highly sensitive function OmpF, LamB glycoporin different Indeed, level more responsive to medium osmolarity suggested significant additional layer control over porin-regulatory network.