Molecular structure of nicked DNA: a substrate for DNA repair enzymes.
The molecular structure of a nicked dodecamer DNA double helix, made of a ternary system containing d(CGCGAAAACGCG) + d(CGCGTT) + d(TTCGCG) oligonucleotides, has been determined by x-ray diffraction analysis at 3 A resolution. The molecule adopts a B-DNA conformation, not unlike those found in intact dodecamer DNA molecules crystallized in a somewhat different crystal lattice, despite a gap due to the absence of a phosphate group in the molecule. The helix has a distinct narrow minor groove near the center of the molecule at the AAAA region. This suggests that the internal stabilizing forces due to base stacking and hydrogen-bonding interactions are sufficient to overcome the loss of connectivity associated with the disruption of the covalent backbone of DNA.
Aymami
J
J
Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
Coll
M
M
van der Marel
G A
GA
van Boom
J H
JH
Wang
A H
AH
Rich
A
A
D001483:Base Sequence; D004247:DNA / Q000648:ultrastructure*; D004260:DNA Repair; D005583:Fourier Analysis; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D009838:Oligodeoxyribonucleotides / Q000138:chemical synthesis; D013379:Substrate Specificity; D014961:X-Ray Diffraction
D009838:Oligodeoxyribonucleotides; D004247:DNA