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Arginine Dynamics in a Membrane‐Bound Cationic Beta‐Hairpin Peptide from Solid‐State NMR
Author(s) -
Tang Ming,
Waring Alan J.,
Hong Mei
Publication year - 2008
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.200800005
Subject(s) - chemistry , membrane , peptide , nuclear magnetic resonance spectroscopy , magic angle spinning , solid state nuclear magnetic resonance , crystallography , magainin , biophysics , antimicrobial peptides , stereochemistry , nuclear magnetic resonance , biochemistry , physics , biology
The site‐specific motion of Arg residues in a membrane‐bound disulfide‐linked antimicrobial peptide, protegrin‐1 (PG‐1), was investigated by using magic‐angle‐spinning solid‐state NMR spectroscopy to better understand the membrane insertion and lipid interaction of this cationic membrane‐disruptive peptide. The C–H and N–H dipolar couplings and 13 C chemical shift anisotropies were measured in the anionic POPE/POPG membrane, and were found to be reduced from the rigid‐limit values by varying extents; this indicates the presence of segmental motion. An Arg residue at the β‐turn region of the peptide showed much weaker spin interactions, which indicates larger amplitudes of motion than an Arg residue in the β‐strand region of the peptide. This is consistent with the exposure of the β turn to the membrane surface and the immersion of the β strand in the hydrophobic middle of the membrane, and supports the previously proposed oligomerization of the peptide into β barrels in the anionic membrane. The 13 C T 2 and 1 H T 1 ρ relaxation times indicate that the β‐turn backbone undergoes large‐amplitude intermediate‐timescale motion in the fluid phase of the membrane; this causes significant line broadening and loss of spectral intensity. This study illustrates the strong correlation between the dynamics and structure of membrane proteins, and the capability of solid‐state NMR spectroscopy to provide detailed information on site‐specific dynamics in complex membrane‐protein assemblies.