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肽和糖中C?H 和C=O的非谐性相互作用
王建平*
作者单位E-mail
王建平* 中国科学院化学研究所分子动力学国家重点实验室, 北京100080 jwang@iccas.ac.cn 
摘要:
C?H和C=O是溶液中蛋白质和多肽的结构和动力学的两个探针,利用振动态的二阶微扰处理,研究了C?H和C=O 两种伸缩振动振动模式在肽类和糖类中的非谐性,并考察了高阶力常数在振动模的局域性和非谐性等方面的作用.结果表明C?H振动模是高度局域化的,其对角非谐性常数主要由模自身决定.但对C=O伸缩振动而言,振动模有很大程度的离域化,其对角非谐性常数由模自身及模间相互作用共同决定.研究还发现,氘代分子中的C?D和C=O的非对角非 谐性常数是负的,不同于非氘代分子中的情形;并且,对非对角非谐性常数贡献较大的模间相互
关键词:  非谐性常数,二维红外光谱,肽类,糖类,振动相互作用
DOI:10.1088/1674-0068/20/04/475-482
分类号:
基金项目:中国科学院百人计划
Anharmonic C?H and C=O Interactions in Peptide and Sugar
Jian-ping Wang*
Abstract:
C?H and C=O stretching modes are two among many structural and dynamic probes of proteins and peptides in condensed phases. Anharmonic properties of these two modes in peptide and sugar have been examined using a second-order perturbative vibrational approach. High order force constants were obtained and examined to ˉnd how crucial they are in determining the degree of mode localization and the nature of mode anharmonicity of the two stretching modes. It is found that the C?H mode is highly localized, and its diagonal anharmonicity is mainly determined by the mode itself. However, the C=O mode is largely delocalized, and the diagonal anharmonicity involves contributions from other modes. The o?-diagonal anharmonicity between C?D and C=O modes is found to be negative in deuterated species, di?ering from those of the non-deuterated ones. It is also found that inter-mode interaction between each of the two modes with low-frequency modes contribute signiˉcantly to the o?-diagonal anharmonicity. These low-frequency modes give rise to a network of energy relaxation or intramolecular vibrational energy redistribution pathways which can be used to examine temporal behavior of intramolecular vibration energy °ow, provided a femtosecond broadband two-dimensional infrared spectroscopy is available.
Key words:  Anharmonicity, Two-dimensional infrared spectroscopy, Peptide, Sugar, Vibrational interaction