Selectivity in ROS-Induced Peptide Backbone Bond Cleavage

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• 作者：Hannah M. Stringfellow ; Michael R. Jones ; Mandy C. Green ; Angela K. Wilson ; Joseph S. Francisco
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：December 4, 2014
• 年：2014
• 卷：118
• 期：48
• 页码：11399-11404
• 全文大小：241K
• ISSN：1520-5215

文摘

Post-translational mechanisms of protein oxidation as a result of reactive oxygen species (ROS) can occur under physiological conditions to yield selective side-chain and backbone modifications including abstractions, donations, additions, substitutions, and fragmentation. In order to characterize the selectivity of radical-mediated fragmentation, quantum mechanical investigations using ab initio and density functional methods were employed to evaluate site, conformation, and pathway trends of small trialanine peptides resembling a 尾-strand and a 尾-turn. Comparisons of reaction enthalpies show that the diamide pathway is more energetically favorable than the 伪-amidation pathway and that both pathways are site and conformationally selective. These findings readily contribute to the understanding of oxidative stress in biochemical processes.