ABSTRACT
ABBREVIATIONS: χ1: side chain torsion angle around Cα-Cβ; θ: angle between the spin interaction tensor and the membrane normal; ϕ: second polar angle describing the alignment of an asymmetric spin interaction tensor with respect to the
membrane normal; τ: angle describing the tilt of a peptide in the membrane; ρ: azimuthal rotation angle of a peptide in the membrane; 3F-Ala: 3-fluoro-alanine; 4F-Phg: 4-fluoro-phenylglycine; Aib: aminoisobutyric acid; CSA: chemical shift anisotropy; CF3-Ala: 2-trifluoromethyl-alanine; CF3-Phg; 4-trifluoromethyl-phenylglycine; DIC: diisopropylcatbodiimide; DLPC: dilauryl-phosphatidylchonline; DMPC: dimyristoyl-phosphatidylcholine; DPPC: dipalmitoyl-phosphatidylcholine; F3-Ala: 3,3,3-trifluoro-alanine; HOBt: O-(1H-benzoxytriazole); MAS: magic-angle spinning: N: membrane normal; r: distance between two 19F-labels; POPC: palmitoyl-oleoyl-phosphatidylcholine; REDOR: rotational echo double resonance; TFA: trifluoroacetic acid; TFE: trifluoroethanol
KEY WORDS: biomembranes, 19F-NMR, fluorine labeling, antimicrobial peptides fusogenic peptides
This chapter is focused on solid-state 19F-nuclear magnetic resonance (NMR) studies of membrane-active peptides, including an outline of synthetic labeling strategies and an overview of the results on several biologically relevant systems. The methodological considerations and fundamental 19F-NMR parameters have been recently discussed in a complementary review;1 hence, no NMR details or technical explanations will be given here. Instead, the emphasis lies on the general approach of resolving the structures and monitoring structural changes of peptides in model membranes in a highly sensitive manner.
