title: Spectroscopic studies of the interactions of the pyrethroid insecticide fenvalerate with gramicidin.
abstract: Fenvalerate is a pyrethroid insecticide which interacts with ionic channels. Using circular dichroism technique we have studied the interaction of fenvalerate with gramicidin, a model channel peptide which transports ions. In most organic solvents, gramicidin exists as a double helix except in trifluoroethanol where it exists as a channel forming single stranded beta6.3 helical monomer. In model lipid membranes, under certain experimental conditions, gramicidin exists as a channel forming single stranded beta6.3 helical dimer. Our results show that fenvalerate interacts more with the single stranded beta6.3 helical monomer or dimer than with the double helical form of gramicidin. This was further confirmed by an increase in the rate of gramicidin mediated proton transport in liposomes by fenvalerate, using the pH sensitive fluorophore, pyranine.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore.
authors.forename: J K
authors.initials: JK
authors.lastname: Ghosh
authors.forename: S N
authors.initials: SN
authors.lastname: Sarkar
authors.forename: S K
authors.initials: SK
authors.lastname: Sikdar
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology*; D001693:Biological Transport, Active / Q000187:drug effects; D002942:Circular Dichroism; D004347:Drug Interactions; D006096:Gramicidin / Q000737:chemistry / Q000494:pharmacology*; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008081:Liposomes; D009570:Nitriles; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011722:Pyrethrins / Q000737:chemistry / Q000494:pharmacology*; D012997:Solvents; D014270:Trifluoroethanol
chemical_list: D000900:Anti-Bacterial Agents; D007306:Insecticides; D007473:Ion Channels; D008081:Liposomes; D009570:Nitriles; D011722:Pyrethrins; D012997:Solvents; D006096:Gramicidin; D014270:Trifluoroethanol; C017690:fenvalerate