Lipid and membrane mimetic environments modulate spin label side chain configuration in the outer membrane protein A.

ABSTRACT: In the present work, the factors that determine EPR line shapes from spin labels at the protein-hydrocarbon interface of a β-barrel membrane protein are examined. The EPR spectra from hydrocarbon facing sites in the outer membrane protein A (OmpA) are highly dependent upon the detergent or lipid into which OmpA is reconstituted. In general, line shapes at these sites are correlated with the solvent accessibility in the supporting amphiphile. A notable exception is CHAPS, which yields rigid limit EPR line shapes for labels at every position along a transmembrane β-strand in OmpA. EPR line shapes from the surface of OmpA are not strongly influenced by steric interference with neighboring side chains, but are modulated by solutes that should interact with hydrophobic surfaces. These results s

SUBMITTER: Jimenez RH 

PROVIDER: S-EPMC3237940 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature