title: DNA structural transitions induced by divalent metal ions in aqueous solutions.
abstract: Using methods of IR spectroscopy, light scattering, gel-electrophoresis DNA structural transitions are studied under the action of Cu2+, Zn2+, Mn2+, Ca2+ and Mg2+ ions in aqueous solution. Cu2+, Zn2+, Mn2+ and Ca2+ ions bind both to DNA phosphate groups and bases while Mg2+ ions-only to phosphate groups of DNA. Upon interaction with divalent metal ions studied (except for Mg2+ ions) DNA undergoes structural transition into a compact form. DNA compaction is characterized by a drastic decrease in the volume occupied by DNA molecules with reversible formation of DNA dense particles of well-defined finite size and ordered morphology. The DNA secondary structure in condensed particles corresponds to the B-form family. The mechanism of DNA compaction under Mt2+ ion action is not dominated by electrostatics. The effectiveness of the divalent metal ions studied to induce DNA compaction correlates with the affinity of these ions for DNA nucleic bases: Cu2+>>Zn2+>Mn2+>Ca2+>>Mg2+. Mt2+ ion interaction with DNA bases (or Mt2+ chelation with a base and an oxygen of a phosphate group) may be responsible for DNA compaction. Mt2+ ion interaction with DNA bases can destabilize DNA causing bends and reducing its persistent length that will facilitate DNA compaction.
authors.affiliation: B.I. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47 Lenin Avenue, 61164 Kharkov, Ukraine. o.hackl@manchester.ac.uk
authors.forename: Elene V
authors.initials: EV
authors.lastname: Hackl
authors.forename: Svetlana V
authors.initials: SV
authors.lastname: Kornilova
authors.forename: Yurij P
authors.initials: YP
authors.lastname: Blagoi
mesh_terms: D000818:Animals; D002412:Cations / Q000737:chemistry; D002417:Cattle; D004247:DNA / Q000737:chemistry*; D008670:Metals / Q000737:chemistry*; D009690:Nucleic Acid Conformation; D013055:Spectrophotometry, Infrared
chemical_list: D002412:Cations; D008670:Metals; D004247:DNA; C427203:calf thymus DNA