Conformational transitions of the phosphodiester backbone in native DNA: two-dimensional magic-angle-spinning 31P-NMR of DNA fibers.
Solid-state 31P-NMR is used to investigate the orientation of the phosphodiester backbone in NaDNA-, LiDNA-, MgDNA-, and NaDNA-netropsin fibers. The results for A- and B-DNA agree with previous interpretations. We verify that the binding of netropsin to NaDNA stabilizes the B form, and find that in NaDNA, most of the phosphate groups adopt a conformation typical of the A form, although there are minor components with phosphate orientations close to the B form. For LiDNA and MgDNA samples, on the other hand, we find phosphate conformations that are in variance with previous models. These samples display x-ray diffraction patterns that correspond to C-DNA. However, we find two distinct phosphate orientations in these samples, one resembling that in B-DNA, and one displaying a twist of the PO4 groups about the O3-P-O4 bisectors. The latter conformation is not in accordance with previous models of C-DNA structure.
Song
Z
Z
Division of Physical Chemistry, Arrhenius Laboratory, University of Stockholm, Sweden.
Antzutkin
O N
ON
Lee
Y K
YK
Shekar
S C
SC
Rupprecht
A
A
Levitt
M H
MH
D018360:Crystallography, X-Ray / Q000379:methods; D004247:DNA / Q000737:chemistry*; D008094:Lithium; D008274:Magnesium; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D009429:Netropsin; D009690:Nucleic Acid Conformation; D010758:Phosphorus; D012964:Sodium
D010758:Phosphorus; D009429:Netropsin; D004247:DNA; D008094:Lithium; D012964:Sodium; D008274:Magnesium