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Temperature dependence and resonance assignment of 13 C NMR spectra of selectively and uniformly labeled fusion peptides associated with membranes
Author(s) -
Bodner Michele L.,
Gabrys Charles M.,
Parkanzky Paul D.,
Yang Jun,
Duskin Craig A.,
Weliky David P.
Publication year - 2004
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1331
Subject(s) - chemistry , chemical shift , membrane , peptide , popc , nuclear magnetic resonance spectroscopy , magic angle spinning , solid state nuclear magnetic resonance , nmr spectra database , fusion , magnetic dipole–dipole interaction , crystallography , resonance (particle physics) , analytical chemistry (journal) , spectral line , lipid bilayer , nuclear magnetic resonance , stereochemistry , chromatography , dipole , organic chemistry , biochemistry , astronomy , physics , linguistics , philosophy , particle physics
HIV‐1 and influenza viral fusion peptides are biologically relevant model fusion systems and, in this study, their membrane‐associated structures were probed by solid‐state NMR 13 C chemical shift measurements. The influenza peptide IFP‐L2CF3N contained a 13 C carbonyl label at Leu‐2 and a 15 N label at Phe‐3 while the HIV‐1 peptide HFP‐UF8L9G10 was uniformly 13 C and 15 N labeled at Phe‐8, Leu‐9 and Gly‐10. The membrane composition of the IFP‐L2CF3N sample was POPC–POPG (4:1) and the membrane composition of the HFP‐UF8L9G10 sample was a mixture of lipids and cholesterol which approximately reflects the lipid headgroup and cholesterol composition of host cells of the HIV‐1 virus. In one‐dimensional magic angle spinning spectra, labeled backbone 13 C were selectively observed using a REDOR filter of the 13 C– 15 N dipolar coupling. Backbone chemical shifts were very similar at −50 and 20°C, which suggests that low temperature does not appreciably change the peptide structure. Relative to −50°C, the 20°C spectra had narrower signals with lower integrated intensity, which is consistent with greater motion at the higher temperature. The Leu‐2 chemical shift in the IFP‐L2CF3N sample correlates with a helical structure at this residue and is consistent with detection of helical structure by other biophysical techniques. Two‐dimensional 13 C– 13 C correlation spectra were obtained for the HFP‐UF8L9G10 sample and were used to assign the chemical shifts of all of the 13 C labels in the peptide. Secondary shift analysis was consistent with a β‐strand structure over these three residues. The high signal‐to‐noise ratio of the 2D spectra suggests that membrane‐associated fusion peptides with longer sequences of labeled amino acids can also be assigned with 2D and 3D methods. Copyright © 2004 John Wiley & Sons, Ltd.