二价
化学
DNA
水溶液
水溶液中的金属离子
螯合作用
结晶学
分子
离子
金属
无机化学
生物化学
有机化学
作者
Elene V. Hackl,С. В. Корнилова,Yu. P. Blagoı̆
标识
DOI:10.1016/j.ijbiomac.2005.01.011
摘要
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.
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