title: High regularity of Z-DNA revealed by ultra high-resolution crystal structure at 0.55 A.
abstract: The crystal structure of a Z-DNA hexamer duplex d(CGCGCG)(2) determined at ultra high resolution of 0.55 Å and refined without restraints, displays a high degree of regularity and rigidity in its stereochemistry, in contrast to the more flexible B-DNA duplexes. The estimations of standard uncertainties of all individually refined parameters, obtained by full-matrix least-squares optimization, are comparable with values that are typical for small-molecule crystallography. The Z-DNA model generated with ultra high-resolution diffraction data can be used to revise the stereochemical restraints applied in lower resolution refinements. Detailed comparisons of the stereochemical library values with the present accurate Z-DNA parameters, shows in general a good agreement, but also reveals significant discrepancies in the description of guanine-sugar valence angles and in the geometry of the phosphate groups.
authors: Synchrotron Radiation Research Section, MCL, National Cancer Institute, Argonne National Laboratory, Argonne, IL 60439, USA.
authors: Krzysztof
authors: K
authors: Brzezinski
authors: Anna
authors: A
authors: Brzuszkiewicz
authors: Miroslawa
authors: M
authors: Dauter
authors: Maciej
authors: M
authors: Kubicki
authors: Mariusz
authors: M
authors: Jaskolski
authors: Zbigniew
authors: Z
authors: Dauter
mesh_terms: D020029:Base Pairing; D018360:Crystallography, X-Ray; D043542:DNA, Z-Form / Q000737:chemistry*; D008958:Models, Molecular; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry
chemical_list: D043542:DNA, Z-Form; D014867:Water