Me. Hatcher et al., A SOLID-STATE DEUTERIUM NMR-STUDY OF THE LOCALIZED DYNAMICS AT THE C9PG10 STEP IN THE DNA DODECAMER [D(CGCCAATTCGCG)](2), Journal of the American Chemical Society, 120(38), 1998, pp. 9850-9862
A solid-state deuterium NMR study of localized mobility at the C9pG10
step in the DNA dodecamer [d(CGCGAATTTCCCG)](2) is described. Zn contr
ast to the results of earlier deuterium NMR studies of furanose ring a
nd backbone dynamics within the d(AATT) moiety, the furanose ring and
helix backbone of dC9 display large amplitudes of motion on the 0.1 ms
time scale at hydration levels characteristic of the B form structure
. Solid-state deuterium NMR line shape data obtained from labeled dC9
DNA are interpreted using a composite motion model, in which the DNA o
ligomer is treated as rotating as a whole about the helix axis, while
the base, furanose ring, and phosphodiester backbone execute localized
motions. Consistent with past solid-state NMR studies, the amplitude
and rate of the uniform relation of the dC9-labeled oligomer are found
to be sensitive to hydration level. Amplitudes of localized reorienta
tional motions of C-D bonds in the furanose ring and backbone of dC9 a
re found to be larger than the librational amplitudes for the C-D bond
s in the base of dC9, indicating that the pyrimidine base sugar does n
ot move as a rigid entity and intersects a locally flexible region of
the phosphodiester backbone. At hydration levels corresponding to 10-1
2 waters per nucleotide, Zeeman relaxation times for the furanose ring
and backbone deuterons of dC9 in B form DNA equal 0.025 and 0.03 ms,
respectively, and are the shortest relaxation times observed thus far
for any deuteron in the DNA dodecamer at comparable hydration levels.
The results of this solid-state NMR study suggest the existence of a s
ignificant dynamic component of sequence-specific recognition in this
system.