title: [Change in lipid-protein interactions in the membranes of bacteria exposed to gramicidin S].
abstract: Effect of cyclopeptide antibiotic gramicidin S on some enzymes and physical state of isolated Micrococcus lysodeikticus membranes is studied. Malate and lactate dehydrogenases were monotonously inhibited under the increase of gramicidin S concentration, while the activity of NADH-dehydrogenase firstly decreased and then reversed to the initial level under further increase of gramicidin S concentration. The oxygen uptake under oxidation of NADH and malate with membranes almost completely inhibited by the antibiotic, while the activity of ascorbate-TMPD-oxidase activity slightly inhibited by the same concentration of gramicidin. The addition of Triton X-100 completely eliminated the inhibitory effect of gramicidin on malate dehydrogenase. The introduction into the membrane of spine probes (2,2,6,6-tetramethyl-4-palmitoylamidopiperidine-1-oxile and 2(14-carboxytetradecyl)-2-ethyl-4,4-dimethyl-3-oxyazolidinyloxile) revealed that gramicidin caused the condensation of membrane lipid component. It is suggested that ionic interaction of gramicidin S with membrane phospholipids brings to "a freezing" of lipids which is a direct cause of impairing the activity of membrane respiration enzymes and the change of their position in the lipid matrix, thus inhibiting energy-producing processes in cell.
mesh_terms: D001204:Ascorbate Oxidase / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D006096:Gramicidin / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D050356:Lipid Metabolism; D008291:Malate Dehydrogenase / Q000378:metabolism; D008566:Membranes / Q000187:drug effects; D008837:Micrococcus / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006096:Gramicidin; D007770:L-Lactate Dehydrogenase; D008291:Malate Dehydrogenase; D001204:Ascorbate Oxidase; D009247:NADH, NADPH Oxidoreductases
vernacular_title: Izmenenie lipid-belkovykh vzaimodeĭstvii v membrane bakteriĭ pri deĭstvii gramitsidina S