title: Unsaturated lipids protect the integral membrane peptide gramicidin A from singlet oxygen.
abstract: In contrast to expectations that unsaturated fatty acids contribute to oxidative stress by providing a source of lipid peroxides, we demonstrated the protective effect of double bonds in lipids on oxidative damage to membrane proteins. Photodynamic inactivation of gramicidin channels was decreased in unsaturated lipid compared to saturated lipid bilayers. By estimating photosensitizer (boronated chlorine e6 amide) binding to the membrane with the current relaxation technique, the decrease in gramicidin photoinactivation was attributed to singlet oxygen scavenging by double bonds in lipids rather than to the reduction in photosensitizer binding. Gramicidin protection by unsaturated lipids was also observed upon induction of oxidative stress with tert-butyl hydroperoxide.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation. Electronic address: rokitskaya@genebee.msu.ru.
authors.forename: Tatyana I
authors.initials: TI
authors.lastname: Rokitskaya
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.
authors.forename: Elena A
authors.initials: EA
authors.lastname: Kotova
authors.affiliation: Biological Department, Lomonosov Moscow State University, Moscow, Russian Federation; Academician V.I.Shumakov Federal Research Center of Transplantology and Artificial Organs, Moscow, Russian Federation.
authors.forename: Igor I
authors.initials: II
authors.lastname: Agapov
authors.affiliation: Biological Department, Lomonosov Moscow State University, Moscow, Russian Federation.
authors.forename: Mikhail M
authors.initials: MM
authors.lastname: Moisenovich
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation.
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Antonenko
mesh_terms: D000327:Adsorption; D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D006096:Gramicidin / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry*; D008564:Membrane Potentials; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010713:Phosphatidylcholines / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry*; D020122:tert-Butylhydroperoxide / Q000737:chemistry
chemical_list: D005231:Fatty Acids, Unsaturated; D008051:Lipid Bilayers; D016877:Oxidants; D010713:Phosphatidylcholines; D006096:Gramicidin; D026082:Singlet Oxygen; C021016:1,2-diphytanoylphosphatidylcholine; C002448:1,2-linoleoylphosphatidylcholine; D020122:tert-Butylhydroperoxide; C017251:1,2-oleoylphosphatidylcholine
keywords: Adsorption; Bilayer lipid membrane; Gramicidin channel; Photosensitizer; Singlet oxygen; Unsaturated lipid