Triple helix structures: sequence dependence, flexibility and mismatch effects.
By means of molecular modelling, electrostatic interactions are shown to play an important role in the sequence-dependent structure of triple helices formed by a homopyrimidine oligonucleotide bound to a homopurine. homopyrimidine sequence on DNA. This is caused by the presence of positive charges due to the protonation of cytosines in the Hoogsteen-bonded strand, required in order to form C.GxC+ triplets. Energetic and conformational characteristics of triple helices with different sequences are analyzed and discussed. The effects of duplex mismatches on the triple helix stability are investigated via thermal dissociation using UV absorption.
Sun
J S
JS
Laboratoire de Biophysique, INSERM U201, CNRS UA481, Paris, France.
Mergny
J L
JL
Lavery
R
R
Montenay-Garestier
T
T
Hélène
C
C
D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011685:Purine Nucleotides / Q000737:chemistry; D011742:Pyrimidine Nucleotides / Q000737:chemistry; D012689:Sequence Homology, Nucleic Acid; D013816:Thermodynamics
D009838:Oligodeoxyribonucleotides; D011685:Purine Nucleotides; D011742:Pyrimidine Nucleotides; D004247:DNA