Three-dimensional solid-state NMR spectroscopy is essential for resolution of resonances from in-plane residues in uniformly (15)N-labeled helical membrane proteins in oriented lipid bilayers.
Uniformly (15)N-labeled samples of membrane proteins with helices aligned parallel to the membrane surface give two-dimensional PISEMA spectra that are highly overlapped due to limited dispersions of (1)H-(15)N dipolar coupling and (15)N chemical shift frequencies. However, resolution is greatly improved in three-dimensional (1)H chemical shift/(1)H-(15)N dipolar coupling/(15)N chemical shift correlation spectra. The 23-residue antibiotic peptide magainin and a 54-residue polypeptide corresponding to the cytoplasmic domain of the HIV-1 accessory protein Vpu are used as examples. Both polypeptides consist almost entirely of alpha-helices, with their axes aligned parallel to the membrane surface. The measurement of three orientationally dependent frequencies for Val17 of magainin enabled the three-dimensional orientation of this helical peptide to be determined in the lipid bilayer.
Marassi
F M
FM
The Wistar Institute, Philadelphia, PA 19104-4268, USA.
Ma
C
C
Gesell
J J
JJ
Opella
S J
SJ
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D015497:HIV-1; D054298:Human Immunodeficiency Virus Proteins; D008051:Lipid Bilayers / Q000737:chemistry*; D054806:Magainins; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry*; D009587:Nitrogen Isotopes; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D054334:Viral Regulatory and Accessory Proteins / Q000737:chemistry*; D029867:Xenopus Proteins; D000086082:Viroporin Proteins
D023181:Antimicrobial Cationic Peptides; D054298:Human Immunodeficiency Virus Proteins; D008051:Lipid Bilayers; D054806:Magainins; D008565:Membrane Proteins; D009587:Nitrogen Isotopes; D010455:Peptides; D054334:Viral Regulatory and Accessory Proteins; D029867:Xenopus Proteins; C514859:vpu protein, Human immunodeficiency virus 1; D000086082:Viroporin Proteins; C053301:magainin 2 peptide, Xenopus