title: Acid pH decreases OmpF and OmpC channel size in vivo.
abstract: To be effective against gram-negative organisms, beta-lactam antibiotics must be able to penetrate the outer membrane. For Escherichia coli, these compounds generally cross this barrier through non-specific channels in porins OmpF and OmpC. In vitro studies have shown that increased pH induces a switch in the structure of OmpF and OmpC from a small channel conformation to a set of larger-sized channel conformations. In this study, the permeability of two cephalosporins into cells producing either OmpC or OmpF was examined at various pHs. The results suggest that the pH-induced switch in channel size observed in vitro also occurs in vivo.
authors: Department of Biochemistry, Michigan State University, East Lansing 48824.
authors: J C
authors: JC
authors: Todt
authors: E J
authors: EJ
authors: McGroarty
mesh_terms: D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D002509:Cephaloridine / Q000378:metabolism*; D002511:Cephalosporins / Q000378:metabolism*; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D002511:Cephalosporins; C025163:cephalosporin C; D001618:beta-Lactamases; D002509:Cephaloridine