The conformation of pyrethroids bound to lipid bilayers.
A number of pyrethroids have been synthesised containing bromine or iodine atoms in the acid and alcohol moieties. Quenching of the fluorescence of a pyrene-containing fatty acid in phospholipid bilayers has been used to measure the partitioning of the pyrethroids into the bilayers. Comparison of the intensity of the fluorescence of the 3-phenoxybenzyl moiety of the pyrethroids in lipid bilayers with that in organic solvents shows that the 3-phenoxybenzyl moiety is located in a hydrophobic environment; this was confirmed by fluorescence quenching by spin-labelled fatty acids. Self-quenching of the fluorescence of pyrethroids which contain both a bromine-containing acid and a 3-phenoxybenzyl moiety is consistent with a 'horseshoe' conformation for the bound pyrethroid, with the ester group located at the lipid/water interface and the acid and alcohol moieties folded back with both penetrating into the lipid bilayer.
Department of Biochemistry, University of Southampton, U.K.
F
F
Michelangeli
M J
MJ
Robson
J M
JM
East
A G
AG
Lee
D000438:Alcohols; D001593:Benzyl Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism*; D008968:Molecular Conformation; D010713:Phosphatidylcholines; D011722:Pyrethrins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D014867:Water
D000438:Alcohols; D001593:Benzyl Compounds; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D011722:Pyrethrins; D014867:Water; C017251:1,2-oleoylphosphatidylcholine