The impact of hydrogen bonding on amide 1H chemical shift anisotropy studied by cross-correlated relaxation and liquid crystal NMR spectroscopy.

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TitleThe impact of hydrogen bonding on amide 1H chemical shift anisotropy studied by cross-correlated relaxation and liquid crystal NMR spectroscopy.
Publication TypeJournal Article
Year of Publication2010
AuthorsYao, L, Grishaev, A, Cornilescu, G, Bax, A
JournalJ Am Chem Soc
Volume132
Issue31
Pagination10866-75
Date Published2010 Aug 11
ISSN1520-5126
KeywordsAmides, Anisotropy, Computer Simulation, Crystallography, X-Ray, Hydrogen Bonding, Immunoglobulin G, Liquid Crystals, Magnetic Resonance Spectroscopy, Models, Molecular, Reference Standards
Abstract

Site-specific (1)H chemical shift anisotropy (CSA) tensors have been derived for the well-ordered backbone amide moieties in the B3 domain of protein G (GB3). Experimental input data include residual chemical shift anisotropy (RCSA), measured in six mutants that align differently relative to the static magnetic field when dissolved in a liquid crystalline Pf1 suspension, and cross-correlated relaxation rates between the (1)H(N) CSA tensor and either the (1)H-(15)N, the (1)H-(13)C', or the (1)H-(13)C(alpha) dipolar interactions. Analyses with the assumption that the (1)H(N) CSA tensor is symmetric with respect to the peptide plane (three-parameter fit) or without this premise (five-parameter fit) yield very similar results, confirming the robustness of the experimental input data, and that, to a good approximation, one of the principal components orients orthogonal to the peptide plane. (1)H(N) CSA tensors are found to deviate strongly from axial symmetry, with the most shielded tensor component roughly parallel to the N-H vector, and the least shielded component orthogonal to the peptide plane. DFT calculations on pairs of N-methyl acetamide and acetamide in H-bonded geometries taken from the GB3 X-ray structure correlate with experimental data and indicate that H-bonding effects dominate variations in the (1)H(N) CSA. Using experimentally derived (1)H(N) CSA tensors, the optimal relaxation interference effect needed for narrowest (1)H(N) TROSY line widths is found at approximately 1200 MHz.

DOI10.1021/ja103629e
Alternate JournalJ. Am. Chem. Soc.
PubMed ID20681720
PubMed Central IDPMC2915638
Grant ListP41GM66326 / GM / NIGMS NIH HHS / United States
P41RR02301 / RR / NCRR NIH HHS / United States
/ / Intramural NIH HHS / United States