the low-temperature crystal structure of the pure-spermine form of Z-DNA reveals binding of a spermine molecule in the minor groove

Citations Over TimeTop 15% of 1994 papers

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.

Related Papers

• → DNA minor groove interactions and the biological activity of 2,5-bis-[4-(N-alkylamidino)phenyl] furans(2000)35 cited
• → Spermine-DNA interactions: a theoretical study.(1986)162 cited
• → Inhibition of Human DNA Topoisomerase I by New DNA Minor Groove Ligands: Derivatives of Oligo-1,3-Thiazolecarboxamides(2001)5 cited
• → Sugar-DNA Molecular Recognition: Specific Interaction of α-1,4-Glucopyranose Chains with DNA in the Minor Groove(1994)4 cited
• Control over the sequence specificity of DNA alkylation: syntheses and reactions with 32P-end-labelled DNA of N-alkyl-N-nitrosoureas linked to minor groove binding lexitropsins.(1991)