Sigel H
Institute of Inorganic Chemistry, University of Basel, Switzerland.
Biol Trace Elem Res. 1989 Jul-Sep;21:49-59. doi: 10.1007/BF02917236.
The self-association of nucleosides decreases within the series adenosine greater than guanosine greater than inosine greater than cytidine approximately uridine. The same trend is observed for the corresponding nucleotides, though less pronounced, as the charge effect governs series like adenosine much greater than AMP2- greater than ADP3- approximately greater than ATP4-. Protonation of adenosine considerably reduces its self-stacking tendency: this is different with ATP4-, where a maximum is reached for H2(ATP)2- caused by additional ionic interactions in the [H2(ATP)]2(4-) dimer. Metal ion coordination may promote self-association, e.g., of ATP4- via (mainly) charge neutralization (Mg2+) and the formation of intermolecular bridges in dimeric stacks (Zn2+, Cd2+). These results allow definition of conditions with negligible self-association and thus the determination of the stability and structure of monomeric nucleotide complexes in aqueous solution, e.g., quantification of macrochelate formation in M(ATP)2- complexes. Some biological implications of the results are indicated.
核苷的自缔合在腺苷＞鸟苷＞肌苷＞胞苷＞尿苷这一系列中逐渐降低。相应的核苷酸也观察到相同趋势，不过不太明显，因为电荷效应决定了如腺苷＞腺苷酸二价阴离子＞腺苷二磷酸三价阴离子＞腺苷三磷酸四价阴离子这样的序列。腺苷的质子化显著降低了其自身堆积倾向：这与腺苷三磷酸四价阴离子不同，在[H₂(ATP)]²⁻二聚体中，由于额外的离子相互作用，H₂(ATP)²⁻达到了最大值。金属离子配位可促进自缔合，例如腺苷三磷酸四价阴离子通过（主要）电荷中和（Mg²⁺）以及在二聚体堆积中形成分子间桥（Zn²⁺、Cd²⁺）。这些结果使得能够定义自缔合可忽略不计的条件，从而确定水溶液中单体核苷酸复合物的稳定性和结构，例如定量测定M(ATP)²⁻复合物中的大环螯合物形成。文中指出了这些结果的一些生物学意义。
