期刊

ChemPhysChem

标题

High Accuracy of Karplus Equations for Relating Three-Bond J Couplings to Protein Backbone Torsion Angles

作者

Fang Li, Jung Ho Lee, Alexander Grishaev, Jinfa Ying, Ad Bax

摘要

3JC′C′ and 3JHNHα couplings are related to the intervening backbone torsion angle  by standard Karplus equations. Although these couplings are known to be affected by parameters other than , including H-bonding, valence angles and residue type, experimental results and quantum calculations indicate that the impact of these latter parameters is typically very small. The solution NMR structure of protein GB3, newly refined by using extensive sets of residual dipolar couplings, yields 50–60 % better Karplus equation agreement between  angles and experimental 3JC′C′ and 3JHNHα values than does the high-resolution X-ray structure. In intrinsically disordered proteins, 3JC′C′ and 3JHNHα couplings can be measured at even higher accuracy, and the impact of factors other than the intervening torsion angle on 3J will be smaller than in folded proteins, making these couplings exceptionally valuable reporters on the ensemble of  angles sampled by each residue.

原文链接

http://onlinelibrary.wiley.com/doi/10.1002/cphc.201402704/abstract