Summary information and primary citation
- PDB-id
-
131d;
SNAP-derived features in text and
JSON formats
- Class
- DNA
- Method
- X-ray (1.0 Å)
- Summary
- The low-temperature crystal structure of the
pure-spermine form of z-DNA reveals binding of a spermine
molecule in the minor groove
- Reference
-
Bancroft D, Williams LD, Rich A, Egli M (1994): "The
low-temperature crystal structure of the pure-spermine
form of Z-DNA reveals binding of a spermine molecule in
the minor groove." Biochemistry,
33, 1073-1086. doi: 10.1021/bi00171a005.
- Abstract
- The X-ray crystal structure of the pure-spermine form
of the left-handed Z-DNA duplex [d(CGCGCG)]2 has been
determined at a temperature of -110 degrees C. Whereas the
previously described room temperature structure of the
pure-spermine form showed only the presence of a single
"interhelix" spermine molecule, mediating contacts between
neighboring duplexes (Egli et al., 1991), a second
"intrahelix" spermine molecule as well as two hydrated
sodium ions were found in the structure determined at low
temperature. This second spermine molecule binds primarily
within the minor groove of two hexamer duplexes that are
stacked in an end-to-end fashion in the crystal lattice.
Thus, the intrahelix spermine molecule interacts with a
single infinite helix. The spine of hydration observed in
other structures of Z-DNA hexamers is partially replaced
and partially displaced by the intrahelix spermine
molecule. In Z-DNA, phosphate groups are relatively closely
spaced across the minor groove compared to the right-handed
double-helical conformation of B-DNA. The intrahelix
spermine molecule decreases cross-groove electrostatic
repulsion within the Z-DNA helix, thereby increasing its
relative stability. This structure may therefore provide an
explanation for the role of spermine as a very effective
inducer of the conformational B-DNA to Z-DNA transition
with alternating dG-dC sequences in solution.
