title: A possible family of B-like triple helix structures: comparison with the Arnott A-like triple helix.
abstract: Recent experimental studies of the structure of triple helices show that their conformation in solution differs from the A-like structure derived from diffraction data on triple helix fibers by Arnott and co-workers. Here we show by means of molecular modeling that a family of triple helix structures may exist with similar conformational energies, but with a variety of sugar puckers. The characteristics of these putative triple helices are analyzed for three different base sequences: (T.AxT)n, (C.GxC+)n, and alternating (C.GxC+/T.AxT)n. In the case of (C.GxC+)n triple helix, infrared and Raman spectra have been obtained and clearly reveal the existence of both N- and S-type sugars in solution. The molecular mechanics calculations allow us to propose a stereochemically reasonable model for this triple helix, in good agreement with the vibrational spectroscopy results.
authors.affiliation: Laboratoire CSSB, URA CNRS 1430, UFR Santé Médecine et Biologie Humaine, Université Paris XIII, Bobigny, France.
authors.forename: M
authors.initials: M
authors.lastname: Ouali
authors.forename: R
authors.initials: R
authors.lastname: Letellier
authors.forename: F
authors.initials: F
authors.lastname: Adnet
authors.forename: J
authors.initials: J
authors.lastname: Liquier
authors.forename: J S
authors.initials: JS
authors.lastname: Sun
authors.forename: R
authors.initials: R
authors.lastname: Lavery
authors.forename: E
authors.initials: E
authors.lastname: Taillandier
mesh_terms: D000465:Algorithms; D001482:Base Composition; D004247:DNA / Q000737:chemistry*; D046911:Macromolecular Substances; D009690:Nucleic Acid Conformation; D011089:Polydeoxyribonucleotides / Q000737:chemistry*; D012984:Software; D013329:Structure-Activity Relationship
chemical_list: D046911:Macromolecular Substances; D011089:Polydeoxyribonucleotides; D004247:DNA