Title

Identification of Spectroscopic Patterns of CH···O H-Bonds in Proteins

Document Type

Article

Journal/Book Title

Journal of Physical Chemistry B

Publication Date

2009

Publisher

American Chemical Society

Volume

113

Issue

30

First Page

10421

Last Page

10427

DOI

10.1021/jp9035138

Abstract

Ab initio calculations are used to identify characteristics of vibrational and NMR spectra that signal the involvement of a protein backbone in a CH···O H-bond and that distinguish this sort of interaction from other H-bonds in which a protein might participate. Glycine and alanine dipeptides, in both their C7 and C5 minimum-energy structures, are paired with formamide in a number of different H-bonding arrangements. The CH···O H-bond is characterized by a small contraction of the C−H bond length, along with a blue shift in its stretching frequency, accompanied by an intensification of this vibrational band. In the context of NMR spectra, the bridging CH proton’s chemical shift is moved downfield by 1−2 ppm. The aforementioned features are not produced by other H-bonds in which the protein backbone might participate, such as NH proton donation or accepting a proton via the peptide C═O.

Comments

Originally published by American Chemical Society in the Journal of Physical Chemistry.

Publisher's PDF can be accessed through the remote link. May require fee or subscription.