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Biochemistry - Biophysics - Chemistry

13C NMR Reveals No Evidence of n-p* Interactions in Proteins
Published: Thursday, August 02, 2012
Author: Bradley Worley et al.

by Bradley Worley, Georgia Richard, Gerard S. Harbison, Robert Powers

An interaction between neighboring carbonyl groups has been postulated to stabilize protein structures. Such an interaction would affect the C chemical shielding of the carbonyl groups, whose paramagnetic component is dominated by and excitations. Model compound calculations indicate that both the interaction energetics and the chemical shielding of the carbonyl group are instead dominated by a classical dipole-dipole interaction. A set of high-resolution protein structures with associated carbonyl C chemical shift assignments verifies this correlation and provides no evidence for an inter-carbonyl interaction.