Metalloregulation of triple helix formation by control of the loop conformation.
The flexible polypyridine ligand, 2,2':6',2('')-terpyridine (terpy), was built into the backbone of oligonucleotides to form DNA conjugates. The terpy unit functioned as a good loop when the conjugates formed the bimolecular triplexes with complementary oligopurine. The triplex structure was destabilized by the specific interaction with divalent transition metal ions (Cu(2+), Zn(2+), and Fe(2+)), in particular Cu(2+) ions. This ion destabilized one of the triplexes by 4.2 kcalmol(-1) or made the triplex formation constant less than 1/10(3) at 298 K. This result is attributed to the substantial turbulence of the terminal structure of the triplexes.
Ihara
Toshihiro
T
Department of Applied Chemistry and Biochemistry, Graduate School of Science and Technology, Kumamoto University, Kumamoto, Japan. toshi@chem.kumamoto-u.ac.jp
Sato
Yoshinobu
Y
Shimada
Hiroshi
H
Jyo
Akinori
A
D020029:Base Pairing; D004247:DNA / Q000138:chemical synthesis*; D008024:Ligands; D019216:Metals, Heavy / Q000737:chemistry*; D015394:Molecular Structure; D009692:Nucleic Acid Heteroduplexes / Q000737:chemistry*; D009841:Oligonucleotides / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics; D014466:Ultraviolet Rays
D008024:Ligands; D019216:Metals, Heavy; D009692:Nucleic Acid Heteroduplexes; D009841:Oligonucleotides; D011725:Pyridines; C051802:triplex DNA; D004247:DNA