131D

THE LOW-TEMPERATURE CRYSTAL STRUCTURE OF THE PURE-SPERMINE FORM OF Z-DNA REVEALS BINDING OF A SPERMINE MOLECULE IN THE MINOR GROOVE

Summary for 131D

• Entry DOI: 10.2210/pdb131d/pdb
• Descriptor: DNA (5'-D(*CP*GP*CP*GP*CP*G)-3'), SPERMINE, SODIUM ION, ... (4 entities in total)
• Functional Keywords: z-dna, double helix, dna
• Total number of polymer chains: 2
• Total formula weight: 4071.07

Authors

Bancroft, D.,Williams, L.D.,Rich, A.,Egli, M. (deposition date: 1993-06-18, release date: 1993-10-15, Last modification date: 2024-02-07)

Primary citation

Bancroft, D.,Williams, L.D.,Rich, A.,Egli, M.
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, 1994

PubMed 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.

PubMed: 8110738
DOI: 10.1021/bi00171a005

Experimental method

X-RAY DIFFRACTION (1 Å)