title: A novel pyrimidine tetrad contributing to stabilize tetramolecular G-quadruplex structures.
abstract: G-quadruplex structures formed by oligodeoxyribonucleotides TGGU(NH2)GGT (AM, U(NH2) = 5-amino-2'-deoxyuridine), TGGU(Br)GGT (BR, U(Br) = 5-bromo-2'-deoxyuridine) and TGGTGGT (TH) have been investigated through circular dichroism, nuclear magnetic resonance, gel electrophoresis and molecular modeling techniques. Collected data indicate that all 7-mer oligonucleotides form tetramolecular parallel G-quadruplex structures with all residues adopting anti glycosidic bonds. In the case of AM, data suggest the occurrence of a novel U(NH2)-tetrad characterized by eight hydrogen bonds that stabilizes the G-quadruplex structure more efficiently than U(Br)- and T-tetrads.
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy. galeone@unina.it antonella.virgilio@unina.it.
authors.forename: V
authors.initials: V
authors.lastname: Esposito
authors.affiliation: Department of Science, University of Basilicata, Viale dell'Ateneo Lucano 10, I-85100, Potenza, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Pepe
authors.affiliation: Department of Experimental Medicine, Second University of Naples, Via Costantinopoli 16, 80138 Napoli, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Filosa
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy. galeone@unina.it antonella.virgilio@unina.it.
authors.forename: L
authors.initials: L
authors.lastname: Mayol
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy. galeone@unina.it antonella.virgilio@unina.it.
authors.forename: A
authors.initials: A
authors.lastname: Virgilio
authors.affiliation: Department of Pharmacy, University of Naples "Federico II", Via D. Montesano, 49, 80131 Naples, Italy. galeone@unina.it antonella.virgilio@unina.it.
authors.forename: A
authors.initials: A
authors.lastname: Galeone
mesh_terms: D002942:Circular Dichroism; D054856:G-Quadruplexes; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D011743:Pyrimidines / Q000737:chemistry*
chemical_list: D011743:Pyrimidines