蛋白质β-折叠二聚体结合能的理论研究  

Theoretical studies on the binding energy of β-sheet models

作　　者：孙长亮[1] 王长生[1] 

机构地区：[1]辽宁师范大学化学化工学院,大连116029

出　　处：《中国科学（B辑）》2009年第6期481-487,共7页Science in China(Series B)

基　　金：国家自然科学基金(批准号:20573049;20633050);辽宁省教育厅基金(批准号:20060469);辽宁省高校创新团队基金(批准号:2007T091)项目资助

摘　　要：使用B3LYP和MP2方法研究了17个由甘氨酸多肽构成的具有反平行结构和平行结构的β-折叠二聚体.估算了在反平行结构中存在的H···H,O···O二级静电排斥作用的大小.并以LR,SR,MR为结构单元探讨了肽链长度的增加对体系的结合能的影响.结果表明在反平行的β-折叠二聚体中,由于二级静电作用的影响,随着肽链长度的增加,体系的结合能是以折线形式增强的,而在平行结构中,体系的结合能随着肽链长度的增加呈线性增强关系.B3LYP and MP2 methods are used to investigate the binding energy of seventeen antiparallel and parallel β-sheet models. The results indicate that the binding energy obtained from B3LYP calculations is weaker than that obtained from MP2 calculations but the relative binding energy yielded by B3LYP is almost the same as MP2. For the antiparallel β-sheets in which two N-H…O=C hydrogen bonds can form either a large hydrogen-bonded ring or a small hydrogen-bonded ring, the binding energy increases obviously when one large ring unit is added, whereas it only changes slightly when one small ring unit is added because of the secondary electrostatic repulsive interaction existing in the small ring unit which is estimated to be about 20 kJ/mol. For the parallel β-sheet models, the binding energy increases almost exactly linearly with the increase of the chain length.

关 键 词：β-折叠二聚体 氢键 结合能 

分 类 号：Q51[生物学—生物化学]