INTERACTIONS OF A VESICULAR STOMATITIS VIRUS G PROTEIN FRAGMENT WITH PHOSPHATIDYLSERINE : NMR AND FLUORESCENCE STUDIES

Abstract The interaction of a 19 amino acid vesicular stomatitis virus G protein fragment (GTWLNPGFPPQSCGYATVT) with phosphatidylserine-containing model membranes was investigated using solution-phase 1d and 2d 1 H NMR spectroscopy and intrinsic tryptophan fluorescence. Results of these studies show that this peptide interacts with model membranes containing negatively charged phospholipids. The interaction is modulated by both ionic and hydrophobic factors and appears to be dependent on the fluidity and lipid packing of the target bilayer. The data further suggest the existence of two isomeric forms of this peptide, which react differentially with model membranes. Upon binding, 2d 1 H NOESY and tryptophan fluorescence data indicate penetration of the tryptophan residue into the bilayer. A model is proposed for the interaction of the peptide with model membranes, consistent with the experimental findings.