title: Crystal and molecular structure of a DNA duplex containing the carcinogenic lesion O6-methylguanine.
abstract: The crystal and molecular structure of the first DNA duplex containing the carcinogenic lesion O6MeG has been determined to a resolution of 1.9 A and refined to an R factor of 19%. (d[CGC-(O6Me)GCG])2 crystallizes in the left-handed Z DNA form and has crystal parameters and conformational features similar to those of the parent sequence [d(CG)3]2. The methyl groups on O6 of G4 and G10 have C5-C6-O6-O6Me torsion angles of 73 degrees and 56 degrees, respectively, and protrude onto the major groove surface. The base-pairing conformation for the methylated G.C base pairs is of the Watson-Crick type as opposed to a wobble-type conformation that had been proposed in a B DNA fragment. As in other Z DNA structures, a spine of hydration is seen in the minor groove.
authors: Department of Chemistry, Wright-Rieman Laboratories, Rutgers University, Piscataway, New Jersey 08855-0939.
authors: S L
authors: SL
authors: Ginell
authors: S
authors: S
authors: Kuzmich
authors: R A
authors: RA
authors: Jones
authors: H M
authors: HM
authors: Berman
mesh_terms: D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis; D006860:Hydrogen Bonding; D008274:Magnesium; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D009838:Oligodeoxyribonucleotides; D006147:Guanine; D004247:DNA; C008449:O-(6)-methylguanine; D008274:Magnesium