Kennedy S D, Bryant R G
Biophys J. 1986 Oct;50(4):669-76. doi: 10.1016/S0006-3495(86)83507-X.
Ion-DNA interactions are discussed and the applied magnetic field strength dependence of water proton spin-lattice relaxation rates is used to study the Mn(II)-DNA interaction both qualitatively and quantitatively. Associations in which the manganese II (Mn(II)) ion is completely immobilized on the DNA are identified as well as a range of associations in which the ion is only partially reorientationally restricted. Quantitative analysis of the strength of the association in which manganese is immobilized is carried out both with and without a counter-ion condensation correction for electrostatic attraction of the mobile ions. From competition experiments with manganese the relative strengths of the interactions of magnesium and calcium with DNA are found to be identical but less than that of manganese with DNA and the affinity of lithium for DNA is found to be slightly higher than that of sodium. The data demonstrate that the reduced mobility of nonsite-bound ions may have a significant effect on DNA-ion binding analyses performed using magnetic resonance and relaxation methods.
讨论了离子与DNA的相互作用，并利用外加磁场强度对水质子自旋晶格弛豫速率的依赖性，对Mn(II)与DNA的相互作用进行了定性和定量研究。确定了锰(II)离子完全固定在DNA上的结合情况，以及一系列离子仅部分受到重取向限制的结合情况。对锰固定化结合强度进行了定量分析，分析过程中分别考虑了和未考虑移动离子静电吸引的反离子凝聚校正。通过与锰的竞争实验发现，镁和钙与DNA相互作用的相对强度相同，但小于锰与DNA的相互作用强度，且锂对DNA的亲和力略高于钠。数据表明，非位点结合离子迁移率的降低可能对使用磁共振和弛豫方法进行的DNA-离子结合分析产生显著影响。
