title: Membrane-bound penicillin-binding proteins of Escherichia coli. Comparison of a strain carrying an R-factor and the parent strain.
abstract: Membrane-bound penicillin-binding proteins of an Escherichia coli carrying an R factor which mediated the resistance to penicillins were examined by slab gel electrophoresis and fluorography using beta-lactamase inhibitors such as methicillin, clavulanic acid and MC-696-SY2-A, and by affinity chomatography. By fluorography, it appeared that the penicillin-binding proteins of the strain carrying the R factor could not be distinguished from those of the parent strain. In both strains, methicillin had a preferential affinity for penicillin-binding proteins 2 and 3, clavulanic acid for 2 and 4, and MC-696-SY2-A for 1A at the concentration which was needed to inhibit about 75 approximately 80% of beta-lactamase activity of the membrane fraction from a strain carrying an R factor. This with other facts indicates that MC-696-SY2-A has a unique character in the binding to penicillin-binding proteins. By affinity chromatography using cephalexin-CH-Sepharose 4B column, two major cephalexin-binding proteins were detected. Their molecular weights were found to be 110,000 and 32,000, respectively. These two proteins correpsonded to penicillin-binding proteins 1 and 5/6. From these results it was suggested that the R factor had no influence on the penicillin-binding proteins in the E. coli strain examined.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D010400:Penicillin G / Q000378:metabolism; D010405:Penicillinase / Q000378:metabolism; D010406:Penicillins / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D011815:R Factors; D065093:beta-Lactamase Inhibitors
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D010406:Penicillins; D065093:beta-Lactamase Inhibitors; D010405:Penicillinase; D010400:Penicillin G