Solid-state NMR investigations of interaction contributions that determine the alignment of helical polypeptides in biological membranes

Helical peptides reconstituted into oriented phospholipid bilayers were studied by proton-decoupled N-15 solid-state NMR spectroscopy. Whereas hydrophobic channel peptides, such as the N-terminal region of Vpu of HIV-1, adopt transmembrane orientations, amphipathic peptide antibiotics are oriented parallel to the bilayer surface. The interaction contributions that determine the alignment of helical peptides in lipid membranes were analysed using model sequences, and peptides that change their topology in a pH-dependent ma ner have been designed. The energy contributions of histidines, lysines, leucines and alanines as well as the alignment of peptides and phospholipids under conditions of hydrophobic mismatch have been investigated in considerable detail. (C) 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.