title: Large unselective pore in lipid bilayer membrane formed by positively charged peptides containing a sequence of gramicidin A.
abstract: Ion-channel activity of a series of gramicidin A analogues carrying charged amino-acid sequences on the C-terminus of the peptide was studied on planar bilayer lipid membranes and liposomes. It was found that the analogue with the positively charged sequence GSGRRRRSQS forms classical cationic pores at low concentrations and large unselective pores at high concentrations. The peptide was predominantly in the right-handed beta(6.3)-helical conformation in liposomes as shown by circular dichroism spectroscopy. The single-channel conductance of the large pore was estimated to be 320pS in 100mM choline chloride as judged from the fluctuation analysis of the multi-channel current. The analogue with the negatively charged sequence GSGEEEESQS exhibited solely classical cationic channel activity. The ability of a peptide to form different type of channels can be used in the search for broad-spectrum antibiotics.
authors.affiliation: Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia. antonen@genbee.msu.ru
authors.forename: Yuri N
authors.initials: YN
authors.lastname: Antonenko
authors.forename: Tatyana B
authors.initials: TB
authors.lastname: Stoilova
authors.forename: Sergey I
authors.initials: SI
authors.lastname: Kovalchuk
authors.forename: Natalya S
authors.initials: NS
authors.lastname: Egorova
authors.forename: Alina A
authors.initials: AA
authors.lastname: Pashkovskaya
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Sobko
authors.forename: Elena A
authors.initials: EA
authors.lastname: Kotova
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Sychev
authors.forename: Andrey Y
authors.initials: AY
authors.lastname: Surovoy
mesh_terms: D002942:Circular Dichroism; D004594:Electrophysiology; D006096:Gramicidin / Q000737:chemistry / Q000378:metabolism*; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D008051:Lipid Bilayers; D008081:Liposomes; D008564:Membrane Potentials; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary
chemical_list: D007473:Ion Channels; D008051:Lipid Bilayers; D008081:Liposomes; D010455:Peptides; D006096:Gramicidin