Lipopolysaccharide promoted opening of the porin channel.
We show here that the imipenem (a carbapenem, beta-lactam antibiotic)-permeable porin channels (protein D2 or OprD2) of Pseudomonas aeruginosa were closed mostly in the lipopolysaccharide (LPS)-free membrane and were openable by adding LPS to the membrane as assayed by ion conductivity measurements using planar lipid bilayers. Open and closed states of the OprD2 channels exhibited conductivities of about 400 and 30 pS, respectively, in 1 M NaCl. The OprD2 channel in the LPS-containing membrane showed very rapid opening and closing events in a second order and the duration of closure became longer at low membrane potentials.
Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Japan.
J
J
Ishii
T
T
Nakae
D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D015378:Imipenem / Q000378:metabolism; D015640:Ion Channel Gating / Q000187:drug effects; D008051:Lipid Bilayers; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008564:Membrane Potentials; D018272:Porins; D011550:Pseudomonas aeruginosa / Q000378:metabolism*
D001425:Bacterial Outer Membrane Proteins; D008051:Lipid Bilayers; D008070:Lipopolysaccharides; D018272:Porins; D015378:Imipenem