NUCLEAR-MAGNETIC-RESONANCE CHARACTERIZATION OF THE MYRISTOYLATED, N-TERMINAL FRAGMENT OF ADP-RIBOSYLATION FACTOR-1 IN A MAGNETICALLY ORIENTED MEMBRANE ARRAY

The behavior of the N-terminal fragment of human ADP-ribosyladon facto r 1 (ARF1) in a membranelike environment is described. This is accompl ished using heteronuclear liquid crystal NMR techniques in a magnetica lly oriented membrane array on a selectively C-13- and N-15-labeled pe ptide. After full assignment of the labeled sites, residual dipolar co uplings (C-13-C-13, N-15-H-1 and, C-13-N-15) and chemical shift anisot ropy effects (amide C-13 and N-15) were measured. The experimental dat a were interpreted using order matrix calculations to yield orientatio nal and dynamic information for four separate, rigid amide planes. The experimental data obtained proves that the amphipathic peptide intera cts with the bilayer in a mode that is consistent with an a-helix havi ng its axis parallel to the membrane surface. Possibilities of extendi ng the employed techniques to larger and uniformly labeled systems are discussed.