Aggregation of transmembrane peptides studied by spin-label EPR.

摘要: The structure and function of membrane proteins is partly determined by the interaction these with lipids membrane. Peptides forming single membrane-spanning alpha-helices, such as WALP peptide (acetyl-GWWL(AL)(n)WWA-amide), are good models for interactions. This can be studied investigating aggregation peptides. If peptides remain isolated in membrane, peptide-lipid dominates, if aggregate, peptide-peptide stronger. intrinsic dynamics disordered nature system require new approaches to determine eventual aggregation. We performed electron paramagnetic resonance (EPR) on spin-labeled (SL-WALP) gel liquid-crystalline phases two different phospholipids, saturated DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine), unsaturated DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine). At low temperatures (120 K) where both phase, less extensive observed compared DPPC. Together previous data from atomic force microscopy fluorescence spectroscopy at 294 K ( Sparr ; et al. Biochemistry 2005 , 44 2 -10 ), results suggest that 120 form line aggregates cluster In phase lipids, signatures absent, showing this accommodated either lipid. It concluded lipid case or liquid-crystalline, a more important determinant than whether (DPPC) (DOPC). view gel-phase-like behavior some physiological systems methodology should relevant.