Two-dimensional infrared measurements of the coupling between amide modes of an α-helix
Two-dimensional infrared measurements of the coupling between amide modes of an α-helix
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DOI：
10.1016/j.cplett.2003.10.111
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发表时间：
2003-12-15
影响因子：
2.8
通讯作者：
Hochstrasser, RM
中科院分区：
文献类型：
--
作者：
Fang, C;Wang, J;Hochstrasser, RM
具有C-13=O-16和C-13=O-18标记的双同位素取代的α-螺旋的2D IR光谱使得能够测量由一个、两个和三个残基分离的酰胺-I模式之间的耦合。同位素异构体之间以及它们与螺旋激子带态之间的耦合的幅度和符号证实了螺旋和同位素异构体的状态是离域的。结果与模拟进行了比较。非对角非谐性同意合理的一组耦合，除了最近的邻居，通过键相互作用的耦合修改来自过渡电荷相互作用。(C)2003年由Elsevier B. V.出版
The 2D IR spectra of doubly isotopically substituted alpha-helices with C-13=O-16 and C-13=O-18 labels enabled the couplings between amide-I modes separated by one, two and three residues to be measured. The magnitudes and signs of couplings between the isotopomers and between them and the helix exciton band states confirm that the states of the helix and isotopomers are delocalized. The results are compared with simulations. The off-diagonal anharmonicities agree reasonably with a set of couplings that derive from transition charge interactions except for nearest neighbors for which the coupling is modified by through bond interactions. (C) 2003 Published by Elsevier B.V.