title: Ab initio study of guanine damage by hydroxyl radical.
abstract: Multiconfigurational ab initio methods are used in this study to examine two initial reactions that take place during the OH radical attack of the DNA base guanine: a ring opening reaction and a hydrogen transfer reaction. The same reactions are also studied in the presence of a single water molecule. The ring opening reaction has a moderate barrier height of ∼20-25 kcal/mol that is relatively insensitive to the presence of water. The barrier of the H-transfer reaction, on the other hand, is lowered from ∼50 to ∼22 kcal/mol when one water molecule is added, thus becoming comparable to the barrier height of the ring opening reaction.
authors.affiliation: NASA Ames Research Center , Mail Stop 258-1, P.O. Box 1, Moffett Field, California 94035-0001, United States.
authors.forename: Galina M
authors.initials: GM
authors.lastname: Chaban
authors.forename: Dunyou
authors.initials: D
authors.lastname: Wang
authors.forename: Winifred M
authors.initials: WM
authors.lastname: Huo
mesh_terms: D006147:Guanine / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D017665:Hydroxyl Radical / Q000737:chemistry*; D015394:Molecular Structure; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water; D017665:Hydroxyl Radical; D006147:Guanine; D006859:Hydrogen