title: Comparison between the orthorhombic and tetragonal forms of the heptamer sequence d[GCG(xT)GCG]/d(CGCACGC).
abstract: Cyclohexene nucleic acid (CeNA) building blocks can be introduced into natural DNA sequences without a large conformational influence because of the ability of the six-membered sugar ring to mimic both the C2'-endo and C3'-endo conformations of the naturally occurring ribofuranose sugar ring. The non-self-complementary DNA sequence d[GCG(xT)GCG]/d(CGCACGC) with one incorporated CeNA (xT) moiety crystallizes in two forms: orthorhombic and tetragonal. The tetragonal form, which diffracts to 3 A resolution, is a kinetically stable polymorph of the orthorhombic form [Robeyns et al. (2010), Artificial DNA, 1, 1-7], which diffracts to 1.17 A resolution and is the thermodynamically stable form of the CeNA-incorporated duplex. Here, the two structures are compared, with special emphasis on the differences in crystal packing and the irreversible conversion of the kinetic form into the high-resolution diffracting thermodynamic form.
authors.affiliation: Department of Chemistry, Biomolecular Architecture and BioMacS, Katholieke Universiteit Leuven, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Robeyns
authors.forename: Piet
authors.initials: P
authors.lastname: Herdewijn
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
mesh_terms: D001483:Base Sequence; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D009841:Oligonucleotides; D004247:DNA
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