Structural study of four-stranded quadruplex structures containing 2'-deoxy-8-(propyn-1-yl)adenosine.
In this paper, we report the NMR structural study of two quadruplex structures formed by truncations of the human telomeric sequence and containing a modified base, namely d(AprGGGT) and d(TAprGGGT), where Apr indicates 2'-deoxy-8-(propyn-1-yl)adenosines. Both oligonucleotides have been found to form 4-fold symmetric G-quadruplex structures with all strands parallel and equivalent to each other and characterized by higher thermal stabilities than the natural counterparts. The presence of the propynyl groups affects the conformations of the 5' edge of both quadruplexes in such a way to prevent the formation of one of the two possible H-bond patterns observed for a canonical A-tetrad. The increased thermal stabilities of the modified quadruplexes seem to be mostly due to a prevalent syn glycosidic conformation assumed by the Apr residues.
Dipartimento di Chimica delle Sostanze Naturali, Università degli Studi di Napoli 'Federico II' via D. Montesano 49, I-80131 Naples, Italy.
Veronica
V
Esposito
Antonio
A
Randazzo
Aldo
A
Galeone
Michela
M
Varra
Luciano
L
Mayol
D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D003839:Deoxyadenosines / Q000737:chemistry*; D004355:Drug Stability; D054856:G-Quadruplexes; D006147:Guanine; D006860:Hydrogen Bonding; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013696:Temperature
C492377:2'-deoxy-8-(propyn-1-yl)adenosine; D003839:Deoxyadenosines; D009838:Oligodeoxyribonucleotides; D006147:Guanine; D004247:DNA