title: Structure of the fully modified left-handed cyclohexene nucleic acid sequence GTGTACAC.
abstract: CeNA oligonucleotides consist of a phosphorylated backbone where the deoxyribose sugars are replaced by cyclohexene moieties. The X-ray structure determination and analysis of a fully modified octamer sequence GTGTACAC, which is the first crystal structure of a carbocyclic-based nucleic acid, is presented. This particular sequence was built with left-handed building blocks and crystallizes as a left-handed double helix. The helix can be characterized as belonging to the (mirrored) A-type family. Crystallographic data were processed up to 1.53 A, and the octamer sequence crystallizes in the space group R32. The sugar puckering is found to adopt the 3H2 half-chair conformation which mimics the C3'-endo conformation of the ribose sugar. The double helices stack on top of each other to form continuous helices, and static disorder is observed due to this end-to-end stacking.
authors.affiliation: Katholieke Universiteit Leuven, Department of Chemistry, Biomolecular Architecture and BioMacS, Celestijnenlaan 200F, B-3001 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; D053138:Cyclohexenes / Q000737:chemistry*; D003855:Deoxyribose / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D053138:Cyclohexenes; D009841:Oligonucleotides; C052568:cyclohexene; D003855:Deoxyribose