Halogen-Bonded Guanine Base Pairs, Quartets and Ribbons.

ABSTRACT: Halogen bonding is studied in different structures consisting of halogenated guanine DNA bases, including the Hoogsteen guanine-guanine base pair, two different types of guanine ribbons (R-I and R-II) consisting of two or three monomers, and guanine quartets. In the halogenated base pairs (except the Cl-base pair, which has a very non-planar structure with no halogen bonds) and R-I ribbons (except the At trimer), the potential N-X•••O interaction is sacrificed to optimise the N-X•••N halogen bond. In the At trimer, the astatines originally bonded to N1 in the halogen bond donating guanines have moved to the adjacent O6 atom, enabling O-At•••N, N-At•••O, and N-At•••At halogen bonds. The brominated and chlorinated R-II trimers contain two N-X•••N and two N-X•••O halogen bonds, whereas in the

SUBMITTER: Thornton NJ 

PROVIDER: S-EPMC7555031 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature