Gas Phase Conformations of Tetrapeptide Glycine-Phenylalanine- Glycine-Glycine  

甘氨酸-苯丙氨酸-甘氨酸-甘氨酸四肽气相稳定构型的系统寻找

作　　者：陈惠宾[1] 王耀[1] 陈欣[1] 林子敬[1] 

机构地区：[1]中国科学技术大学微尺度物质科学国家实验室,合肥230026

出　　处：《Chinese Journal of Chemical Physics》2012年第1期77-85,I0004,共10页化学物理学报（英文）

摘　　要：Systematic search of the potential energy surface of tetrapeptide glycine-phenylalanine- glycine-glycine （GFGG） in gas phase is conducted by a combination of PM3, HF and BHandHLYP methods. The conformational search method is described in detail. The relative electronic energies, zero point vibrational energies, dipole moments, rotational constants, vertical ionization energies and the temperature dependent conformational distributions for a number of important conformers are obtained. The structural characteristics of these conformers are analyzed and it is found that the entropic effect is a dominating factor in determining the relative stabilities of the conformers. The measurements of dipole moments and some characteristic IR mode are shown to be effective approaches to verify the theoreti- cal prediction. The structures of the low energy GFGG conformers are also analyzed in their connection with the secondary structures of proteins. Similarity between the local structures of low energy GFGG conformers and the α-helix is discussed and many β- and γ-turn local structures in GFGG conformers are found.

关 键 词：Potential energy surface Conformational stability Hydrogen bond Entropy effect Secondary structure 

分 类 号：O[理学]