title: Difference in conformational diversity between nucleic acids with a six-membered 'sugar' unit and natural 'furanose' nucleic acids.
abstract: Natural nucleic acids duplexes formed by Watson-Crick base pairing fold into right-handed helices that are classified in two families of secondary structures, i.e. the A- and B-form. For a long time, these A and B allomorphic nucleic acids have been considered as the 'non plus ultra' of double-stranded nucleic acids geometries with the only exception of Z-DNA, a left-handed helix that can be adopted by some DNA sequences. The five-membered furanose ring in the sugar-phosphate backbone of DNA and RNA is the underlying cause of this restriction in conformational diversity. A collection of new Watson-Crick duplexes have joined the 'original' nucleic acid double helixes at the moment the furanose sugar was replaced by different types of six-membered ring systems. The increase in this structural and conformational diversity originates from the rigid chair conformation of a saturated six-membered ring that determines the orientation of the ring substituents with respect to each other. The original A- and B-form oligonucleotide duplexes have expanded into a whole family of new structures with the potential for selective cross-communication in a parallel or antiparallel orientation, opening up a new world for information storage and for molecular recognition-directed self-organization.
authors.affiliation: Laboratory for Medicinal Chemistry, Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
authors.forename: Eveline
authors.initials: E
authors.lastname: Lescrinier
authors.forename: Matheus
authors.initials: M
authors.lastname: Froeyen
authors.forename: Piet
authors.initials: P
authors.lastname: Herdewijn
mesh_terms: D020029:Base Pairing; D004247:DNA / Q000737:chemistry*; D006601:Hexoses / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D009696:Nucleic Acids / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D012313:RNA / Q000737:chemistry*; D012330:RNA, Double-Stranded / Q000737:chemistry; D012266:Ribose / Q000737:chemistry; D013402:Sugar Alcohols / Q000737:chemistry
chemical_list: D006601:Hexoses; D009696:Nucleic Acids; D009841:Oligonucleotides; D010710:Phosphates; D012330:RNA, Double-Stranded; D013402:Sugar Alcohols; C448220:alpha-homo-DNA; D012313:RNA; D012266:Ribose; D004247:DNA