title: Halogen bonding in DNA base pairs.
abstract: Halogen bonding (R-X···Y) is a qualitative analogue of hydrogen bonding that may prove useful in the rational design of artificial proteins and nucleotides. We explore halogen-bonded DNA base pairs containing modified guanine, cytosine, adenine and thymine nucleosides. The structures and stabilities of the halogenated systems are compared to the normal hydrogen bonded base pairs. In most cases, energetically stable, coplanar structures are identified. In the most favorable cases, halogenated base pair stabilities are within 2 kcal mol(-1) of the hydrogen bonded analogues. Among the halogens X = Cl, Br, and I, bromine is best suited for inclusion in these biological systems because it possesses the best combination of polarizability and steric suitability. We find that the most stable structures result from a single substitution of a hydrogen bond for a halogen bond in dA:dT and dG:dC base pairs, which allows 1 or 2 hydrogen bonds, respectively, to complement the halogen bond.
authors.affiliation: Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States.
authors.forename: Anna J
authors.initials: AJ
authors.lastname: Parker
authors.forename: John
authors.initials: J
authors.lastname: Stewart
authors.forename: Kelling J
authors.initials: KJ
authors.lastname: Donald
authors.forename: Carol A
authors.initials: CA
authors.lastname: Parish
mesh_terms: D020029:Base Pairing; D001665:Binding Sites; D004247:DNA / Q000737:chemistry*; D006219:Halogens / Q000737:chemistry*; D006860:Hydrogen Bonding; D011789:Quantum Theory
chemical_list: D006219:Halogens; D004247:DNA