New quadruplex structure of GGA triplet repeat DNA--an intramolecular quadruplex composed of a G:G:G:G tetrad and G(:A):G(:A):G(:A):G heptad, and its dimerization.
The structure of d(GGAGGAGGAGGA) containing four tandem repeats of a GGA triplet sequence has been determined under physiological K+ conditions by NMR. d(GGAGGAGGAGGA) folds into an intramolecular quadruplex composed of a G:G:G:G tetrad and a G(:A):G(:A):G(:A):G heptad. Four G-G segments of d(GGAGGAGGAGGA) are aligned parallel to each other due to seven successive turns of the main chain at each of the GGA and GAGG segments. Two quadruplexes form a dimer stabilized through a stacking interaction between the heptads of the two quadruplexes. On the basis of these results, the biological implications of naturally occurring GGA triplet repeat DNA are discussed.
Matsugami
A
A
Department of Environment and Natural Sciences, Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
Ouhashi
K
K
Kanagawa
M
M
Liu
H
H
Kanagawa
S
S
Uesugi
S
S
Katahira
M
M
D000241:Adenosine / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D004261:DNA Replication; D019281:Dimerization; D054856:G-Quadruplexes; D006147:Guanine / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D009690:Nucleic Acid Conformation; D012091:Repetitive Sequences, Nucleic Acid
D006147:Guanine; D004247:DNA; D000241:Adenosine