On the influence of secondary structure on the α-C-H bond dissociation energy of proline residues in proteins:: a theoretical study

被引：25

作者：

Block, DA ^{[1
]}

Yu, D ^{[1
]}

Armstrong, DA ^{[1
]}

Rauk, A ^{[1
]}

机构：

[1] Univ Calgary, Dept Chem, Calgary, AB T2N 1N4, Canada

来源：

CANADIAN JOURNAL OF CHEMISTRY | 1998年 / 76卷 / 07期

关键词：

proline; beta-turns; free radical; bond dissociation energy; molecular structure; oxidative damage;

D O I：

10.1139/cjc-76-7-1042

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Ab initio computations (B3LYP/6-31G(D), coupled with isodesmic reactions) were used to predict C-alpha-H bond dissociation energies (BDEs) for proline as a residue in a model peptide, intended to mimic the environment in proteins. The environment was further constrained to mimic common proline positions in beta turns of different types. The BDEs were found to be very dependent on the structural constraints imposed by the beta turn type, implying different structure-mediated susceptibilities to free radical damage to proline residues. Unnatural repair of proline (inversion of chirality) was found to be thermodynamically unfavourable. The predicted BDEs for the proline C-alpha-H bond, in ki mol(-1), to an estimated accuracy of +/-10 kJ mol(-1) are as follows: fully optimized trans rotamer, 368.6; fully optimized cis rotamer, 357.7; beta turn type I, 380.7; beta turn type II, 397.8; beta rum type II: 385.4; beta turn type VIa, 374.0; beta turn type VIb, 355.0.

引用

页码：1042 / 1049

页数：8

共 29 条

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