title: Ab initio molecular dynamics simulation study of dissociative electron attachment to dialanine conformers.
abstract: Dissociative electron attachment (DEA) processes of six low-lying conformers (1-6) of dialanine in the gas phase are investigated by using ab initio molecular dynamics simulations. The incoming electron is captured and primarily occupies the virtual molecular orbital π*, which is followed by the different dissociation processes. The electron attachments to conformers 1 and 2 having the stronger N-H···N and O-H···O intramolecular hydrogen bonds do not lead to fragmentations, but two different backbone bonds are broken in the DEAs to conformers 3 (or 4) and 6, respectively. It is interesting that the hydrogen abstraction of -NH from the terminal methyl group -CH3 is found in the roaming dissociation of the temporary anion of conformer 3. The present simulations enable us to have more insights into the peptide backbone bond breaks in the DEA process and demonstrate a promising way toward understanding of the radiation damages of complicated biological system.
authors: Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China , Hefei, Anhui 230026, China.
authors: Wen-Ling
authors: WL
authors: Feng
authors: Shan Xi
authors: SX
authors: Tian
mesh_terms: D004151:Dipeptides / Q000737:chemistry*; D004579:Electron Transport; D006860:Hydrogen Bonding; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D013816:Thermodynamics
chemical_list: D004151:Dipeptides; C002956:alanylalanine