Chapter 1 - Structure and Membrane Interactions of Antimicrobial Peptides as Viewed by Solid-State NMR Spectroscopy

Abstract

Solid-state NMR spectroscopy is a well-suited technique to study the membrane interactions of antimicrobial peptides by taking advantage of the orientational dependence of nuclear spin interactions. This paper discusses several solid-state NMR experiments to extract information on the peptide structure and dynamics as well as on the effect of antimicrobial peptides on model membranes. More specifically, studies of peptide dynamics by 13 C and 15 N CP MAS and static experiments are reported. Also, the peptide orientation and location in membranes can be extracted from 15 N 1D NMR spectra and spin diffusion NMR, whereas PISEMA experiments that correlate 15 N chemical shifts and 15 N– 1 H dipolar couplings allow the complete determination of membrane topology by specifying the peptide orientation and tilt angle. In addition, examples of peptide structure determination by isotropic chemical shifts, internuclear distance and torsion angle measurements are described. Finally, 31 P NMR and 2 H NMR experiments are commonly used to obtain information on both the polar region and the hydrophobic core of phospholipid bilayers. 31 P NMR spectra reflect the nature of lipid phases and the conformation of the phospholipid polar headgroup, whereas 2 H NMR spectra are indicative of acyl chain orientational order.