Role of porin proteins OmpF and OmpC in the permeation of beta-lactams

Abstract
Mutants of Escherichia coli K-12 lacking major outer membrane proteins were obtained by selecting for resistance to the .beta.-lactam cefoxitin. Three classes of resistant strains were found: mutants in ompB, a regulatory locus for proteins OmpF and OmpC; mutants in ompF; and 1 mutant in tpo. The OmpF and OmpC proteins facilitate penetration of .beta.-lactams through the outer membrane.