Görner H, Tossi A B, Stradowski C, Schulte-Frohlinde D
Max-Planck-Institut für Strahlenchemie, Ruhr, F.R.G.
J Photochem Photobiol B. 1988 Jul;2(1):67-89. doi: 10.1016/1011-1344(88)85038-3.
The interactions of tris(2,2'-bipyridyl)ruthenium(II) chloride and tris-(1,10-phenanthroline)ruthenium(II) chloride, Ru(bpy)3Cl2 and Ru(phen)3Cl2 respectively, with nucleic acids were studied by means of absorption spectroscopy and time-resolved and steady state luminescence techniques in unbuffered aqueous solution at room temperature as a function of added salt, oxygen and the [nucleotide]/[sensitizer] ratio (N/S). The hypochromicity of the visible absorption band of Ru(ligand)3(2+) and the changes in the luminescence intensity and luminescence decay kinetics are considerably larger in the presence of double-stranded calf thymus DNA (dsDNA) than in the presence of single-stranded DNA and polynucleotides. This is suggested to be the result of partial intercalation of the ruthenium complex into the dsDNA rather than just its higher charge density with respect to ssDNA. Spectral changes in the presence of dsDNA increase with increasing N/S ratio (maximum changes reached at N/S = 10-12, half-value 3-4). This is postulated to be due to a transition from mainly electrostatic binding to a binding in which partial intercalation plays an increased role. Addition of alkali or alkaline earth salts at very low concentrations stabilizes partial intercalation whereas higher salt concentrations lead to a release of the ruthenium complex from the strand. This effect of the salt cation increases in the order Cs less than Rb less than K less than Na less than Li less than Ba less than Sr less than Ca less than Mg less than Be. For Ru(bpy)3(2+) the presence of 0.5 mM Mg(ClO4)2 or 6 mM NaClO4 are sufficient to release 50% of the ruthenium complexes which are bound to the dsDNA (N/S = 10); the corresponding half-concentrations for Ru(phen)3(2+) are 0.8 mM and 40 mM respectively. The half-concentrations for release increase with increasing N/S ratio and decrease with the ionic radius of the added salt.
通过吸收光谱法以及时间分辨和稳态发光技术，在室温下的无缓冲水溶液中，研究了氯化三（2,2'-联吡啶）钌（II）和氯化三（1,10-菲咯啉）钌（II）（分别为Ru(bpy)₃Cl₂和Ru(phen)₃Cl₂）与核酸的相互作用，该相互作用是作为添加盐、氧气以及[核苷酸]/[敏化剂]比例（N/S）的函数。在存在双链小牛胸腺DNA（dsDNA）的情况下，Ru(配体)₃(2+)可见吸收带的减色效应以及发光强度和发光衰减动力学的变化，比在存在单链DNA和多核苷酸的情况下要大得多。这被认为是钌配合物部分插入dsDNA的结果，而不仅仅是其相对于ssDNA具有更高的电荷密度。在存在dsDNA的情况下，光谱变化随着N/S比例的增加而增加（在N/S = 10 - 12时达到最大变化，半值为3 - 4）。据推测，这是由于从主要的静电结合转变为部分插入起更大作用的结合。在非常低的浓度下添加碱金属或碱土金属盐会稳定部分插入，而较高的盐浓度会导致钌配合物从链上释放。盐阳离子的这种效应按Cs＜Rb＜K＜Na＜Li＜Ba＜Sr＜Ca＜Mg＜Be的顺序增加。对于Ru(bpy)₃(2+)，存在0.5 mM Mg(ClO₄)₂或6 mM NaClO₄足以释放50%与dsDNA结合的钌配合物（N/S = 10）；对于Ru(phen)₃(2+)，相应的半浓度分别为0.8 mM和40 mM。释放的半浓度随着N/S比例的增加而增加，并随着添加盐的离子半径减小而减小。
