Acid–base properties of the nucleic-acid model 2′-deoxyguanylyl(5′→3′)-2′-deoxy-5′-guanylate, d(pGpG)3–, and of related guanine derivatives
作者:Bernd Knobloch、Helmut Sigel、Andrzej Okruszek、Roland K. O. Sigel
DOI:10.1039/b517904a
日期:——
detail. In this study the six deprotonation reactions of H4[d(pGpG)]+ are quantified. The acidity constants for the release of the first proton from the terminal P(O)(OH)2 group (pKa = 0.65) and for one of the (N7)H+ sites (pKa = 2.4) are estimated. The acidity constants of the remaining four deprotonation reactions were measured by potentiometric pH titrations in aqueous solution (25 degrees C; I =
二核苷酸d(pGpG)是一种常用的DNA模型,用于研究DNA与金属离子之间的各种相互作用,但其酸碱性质尚未详细描述。在这项研究中,对H4 [d(pGpG)] +的六个去质子化反应进行了定量。估计了从末端P(O)(OH)2基团释放出第一质子的酸度常数(pKa = 0.65),以及一个(N7)H +位点(pKa = 2.4)的酸度常数。其余四个去质子化反应的酸度常数是通过在水溶液(25摄氏度; I = 0.1 M,NaNO3)中通过电位pH滴定法测量的:第二个(N7)H +,P(O)的去质子化的pKa值2(OH)-,两个(N1)H位分别为2.98、6.56、9.54和10.11。基于这些结果,我们显示了如何估算尚未研究的相关系统的酸度常数,例如 pGpG,它参与轮状病毒RNA聚合酶的起始步骤。简要指出了我们的研究结果与核酸的相关性。