title: Reorganization energy, activation energy, and mechanism of hole transfer process in DNA: a theoretical study.
abstract: The density functional calculations with aug-cc-pVDZ basis sets on cationic guanine-cytosine (GC(+)) and adenine-thymine (AT(+)) base pairs suggest that the cationic charge is almost entirely localized on the G and A units with significant changes in the N-H and N...O distances around the H-bonded area. While the calculated intramolecular reorganization energy (lambda(v)) for a GC base pair (0.75 eV) is remarkably larger than that for an isolated G base (0.49 eV), for the AT base pairs these values (0.44 and 0.40 eV) are almost the same. The gas phase activation energies (E(a)) for GC(+)GC-->GCGC(+), AT(+)AT-->ATAT(+), and GC(+)AT-->GCAT(+) hole transfer processes are 0.19, 0.11, and 0.73 eV with rate constants of 1.69 x 10(11), 3.15 x 10(11), and 4.61(0.168) s(-1), respectively, at 298 K. An alternative mechanism of hole transfer has been proposed on the basis of energy barriers.
authors.affiliation: Chemistry Department, The Pennsylvania State University, DuBois, PA 15801, USA. kub@psu.edu
authors.forename: Arshad
authors.initials: A
authors.lastname: Khan
mesh_terms: D003198:Computer Simulation; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004735:Energy Transfer; D008956:Models, Chemical; D008958:Models, Molecular; D009690:Nucleic Acid Conformation
chemical_list: D004247:DNA