|Proceedings of the National Academy of Sciences of the United States of America (2008) 105:14389-94|
|Northeast Structural Genomics Consortium|
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A recently determined set of 20 NMR-derived conformations of a 48-residue all-alpha-helical protein, (PDB ID code 2JVD), is validated here by comparing the observed (13)C(alpha) chemical shifts with those computed at the density functional level of theory. ...
In addition, a recently introduced physics-based method, aimed at determining protein structures by using NOE-derived distance constraints together with observed and computed (13)C(alpha) chemical shifts, was applied to determine a new set of 10 conformations, (Set-bt), as a blind test for the same protein. A cross-validation of these two sets of conformations in terms of the agreement between computed and observed (13)C(alpha) chemical shifts, several stereochemical quality factors, and some NMR quality assessment scores reveals the good quality of both sets of structures. We also carried out an analysis of the agreement between the observed and computed (13)C(alpha) chemical shifts for a slightly longer construct of the protein solved by x-ray crystallography at 2.0-A resolution (PDB ID code 3BHP) with an identical amino acid residue sequence to the 2JVD structure for the first 46 residues. Our results reveal that both of the NMR-derived sets, namely 2JVD and Set-bt, are somewhat better representations of the observed (13)C(alpha) chemical shifts in solution than the 3BHP crystal structure. In addition, the (13)C(alpha)-based validation analysis appears to be more sensitive to subtle structural differences across the three sets of structures than any other NMR quality-assessment scores used here, and, although it is computationally intensive, this analysis has potential value as a standard procedure to determine, refine, and validate protein structures.
|Crystallography, X-Ray Models, Molecular Bacillus subtilis Protein Structure, Tertiary Reproducibility of Results Carbon Isotopes Nuclear Magnetic Resonance, Biomolecular Bacterial Proteins Hydrogen Bonding Torsion, Mechanical |
|44 (Last update: 04/01/2017 12:20:16pm)|
Quantum-Mechanics-Derived 13Cα Chemical Shifts for Protein Structure Validation
Quantum-mechanics-derived 13Cα chemical shifts for protein structure validation