title: Selectivity in ROS-induced peptide backbone bond cleavage.
abstract: 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 β-strand and a β-turn. Comparisons of reaction enthalpies show that the diamide pathway is more energetically favorable than the α-amidation pathway and that both pathways are site and conformationally selective. These findings readily contribute to the understanding of oxidative stress in biochemical processes.
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907-2084, United States.
authors.forename: Hannah M
authors.initials: HM
authors.lastname: Stringfellow
authors.forename: Michael R
authors.initials: MR
authors.lastname: Jones
authors.forename: Mandy C
authors.initials: MC
authors.lastname: Green
authors.forename: Angela K
authors.initials: AK
authors.lastname: Wilson
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Francisco
mesh_terms: D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism*; D011789:Quantum Theory; D017382:Reactive Oxygen Species / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D010455:Peptides; D017382:Reactive Oxygen Species