title: NMR solution structure of a parallel LNA quadruplex.
abstract: The solution structure of a locked nucleic acid (LNA) quadruplex, formed by the oligomer d(TGGGT), containing only conformationally restricted LNA residues is reported. NMR and CD spectroscopy, as well as molecular dynamics and mechanic calculations, has been used to characterize the complex. The molecule adopts a parallel stranded conformation with a 4-fold rotational symmetry, showing a right-handed helicity and the guanine residues in an almost planar conformation with three well-defined G-tetrads. The thermal stability of Q-LNA has been found to be comparable with that of [r(UGGGU)]4, while a T(m) increment of 20 degrees C with respect to the corresponding DNA quadruplex structure [d(TGGGT)]4 has been observed. The structural features of the LNA quadruplex reported here may open new perspectives for the biological application of LNAs as novel versatile tools to design aptamer or catalyst oligonucleotides.
authors.affiliation: Dipartimento di Chimica delle Sostanze Naturali, Università degli Studi di Napoli Federico II, via D. Montesano 49, I-80131 Napoli, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Randazzo
authors.forename: Veronica
authors.initials: V
authors.lastname: Esposito
authors.forename: Oliver
authors.initials: O
authors.lastname: Ohlenschläger
authors.forename: Ramadurai
authors.initials: R
authors.lastname: Ramachandran
authors.forename: Luciano
authors.initials: L
authors.lastname: Mayola
mesh_terms: D001483:Base Sequence; D002942:Circular Dichroism; D004247:DNA / Q000737:chemistry*; D054856:G-Quadruplexes; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense / Q000737:chemistry*; D010758:Phosphorus; D011522:Protons; D012996:Solutions; D013816:Thermodynamics
chemical_list: D009841:Oligonucleotides; D016376:Oligonucleotides, Antisense; D011522:Protons; D012996:Solutions; C477371:locked nucleic acid; D010758:Phosphorus; D004247:DNA