High resolution nuclear magnetic resonance studies of the conformation and orientation of melittin bound to a lipid-water interface

Abstract

Previously, the size and stoichiometry of mixed micelles of perdeuterated dodecylphosphocholine and melittin were characterized and the 1H NMR spin systems of most amino acid residues of micelle-bound melittin identified. One- and two-dimensional 1H-1H Overhauser experiments have now been used to obtain qualitative information on intramolecular proton-proton distances. These data show that the N-terminal and the C-terminal segments of melittin form two spatially distinct, compact domains; using lipid spin labels these could be located near the micelle surface. For the C-terminal domain a detailed conformation was determined by using the distance contraints from the Overhauser studies as input for a distance geometry algorithm.