title: Polymyxin B octapeptide and polymyxin B heptapeptide are potent outer membrane permeability-increasing agents.
abstract: Polymyxin B octapeptide (PBOP) and polymyxin B heptapeptide (PBHP) were found to be effective permeabilizers of the outer membrane of Escherichia coli and Salmonella typhimurium. PBOP was as effective as polymyxin B nonapeptide (PMBN), the known very potent permeabilizer. As low a PBOP concentration as 1 microgram/ml sensitized E. coli to rifampicin by a factor of 100. Three micrograms of PBOP per ml was sufficient to sensitize this target to all the other tested hydrophobic antibiotics (erythromycin, fusidic acid, clindamycin, and novobiocin) by a factor of 30. Only a slightly higher (3-fold) concentration of PBHP was required for a similar sensitizing effect.
authors.affiliation: Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: H
authors.initials: H
authors.lastname: Matsunaga
authors.forename: M
authors.initials: M
authors.lastname: Vaara
mesh_terms: D000595:Amino Acid Sequence; D002463:Cell Membrane Permeability / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D011112:Polymyxin B / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: C075547:diaminobutyryl-cyclo(diaminobutyryl-diaminobutyryl-phenylalanyl-leucyl-diaminobutyryl-diaminobutyryl-threonyl); C075546:cyclo(diaminobutyryl-diaminobutyryl-phenylalanyl-leucyl-diaminobutyryl-diaminobutyryl-threonyl); C038934:polymyxin B nonapeptide; D011112:Polymyxin B