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Targeted 13 C– 13 C Distance Measurements in a Microcrystalline Protein via J‐Decoupled Rotational Resonance Width Measurements
Author(s) -
van der Wel Patrick C. A.,
Eddy Matthew T.,
Ramachandran Ramesh,
Griffin Robert G.
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900102
Subject(s) - chemistry , anisotropy , microcrystalline , resonance (particle physics) , nuclear magnetic resonance spectroscopy , analytical chemistry (journal) , magic angle spinning , crystallography , nuclear magnetic resonance , nmr spectra database , spectral line , chemical shift , molecular physics , stereochemistry , atomic physics , physics , optics , organic chemistry , astronomy
Targeting the hydrophobic core : Solid‐state NMR rotational resonance width experiments are performed to measure 13 C– 13 C distances between aromatic and aliphatic residues that make up the hydrophobic core of streptococcal protein G (see picture). Their value in structure calculations and the effect of chemical shift anisotropy at high magnetic field are discussed.Rotational resonance width (R 2 W) magic‐angle spinning (MAS) NMR experiments are performed to measure 13 C– 13 C distances in the hydrophobic core of the microcrystalline model protein G B1 . Such inter‐residue distances are of particular value in NMR structure determinations. The experiments are done at a Larmor frequency of 750 MHz 1 H where the contribution of 13 C chemical shift anisotropy (CSA) to the R 2 transfer mechanism is significant. To minimize line broadening in the 2D spectra, we employ a combination of even/odd isotopic labeling with [1,3‐ 13 C] glycerol, and J‐decoupling in the indirect dimension. This results in high‐precision distance measurements between aromatic side chains of three tyrosine residues and distant methyl groups in the hydrophobic core of the protein. Even in the absence of information on the relative orientation of the shift tensors, we obtain relatively high precision data, which can be further improved by additional constraints on the tensor orientations.