文章基本信息

标题：The origin of vibrational mode couplings in various secondary structural motifs of polypeptides
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作者：Andrew Moran ; Shaul Mukamel
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2004
卷号：101
期号：2
页码：506-510
DOI：10.1073/pnas.2533089100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Electrostatic (through-space) and covalent (through-bond) contributions to couplings involving the C[IMG]/medium/dblbond.gif">O and C--N vibrational stretching modes of the amide group in the {alpha}-helix and the parallel and antiparallel {beta}-sheet structures of alanine polypeptides are analyzed. Coupling constants computed at the density functional theory level are compared with the transition dipole coupling model and the complete electrostatic interaction between transition densities. We find that the transition densities of C[IMG]/medium/dblbond.gif">O modes are localized, and the electrostatic mechanism then holds. In contrast, the C--N mode transition densities are delocalized, and covalent contributions to the coupling are significant.