Orioli P, Cini R, Donati D, Mangani S
Nature. 1980 Feb 14;283(5748):691-3. doi: 10.1038/283691a0.
Ternary complexes between metal ions, nucleotides and aromatic heterocyclic amines are being investigated by X-ray diffraction as possible models for enzyme-metal-substrate interactions. Kennard and coworkers have reported the crystal structure of the ATP disodium salt. Although more recently several crystal structures of binary and ternary complexes between metal ions and nucleoside monophosphates have been reported, no structure combining metal complexes with nucleoside di- or triphosphates has been reported. Most divalent metal ions catalyse the nonenzymatic transfer of phosphate from nucleoside polyphosphates to various acceptors. Therefore, these compounds in water solution undergo extensive hydrolysis in the presence of metal ions, leading to the formation of the monophosphates; for instance, at pH 6.5, Cu2+ accelerates the hydrolysis of ATP by a factor of about 300 (ref. 5). We report here the crystal and molecular structure of the complex [Zn(II)-H2ATP-2,2'-bipyridyl]2.4H2O, determined by single crystal X-ray analysis. The complex molecule provides a possible model for ATP transport and phosphate group transfer mechanism.
金属离子、核苷酸和芳香族杂环胺之间的三元配合物正通过X射线衍射进行研究，作为酶-金属-底物相互作用的可能模型。凯纳德及其同事报道了ATP二钠盐的晶体结构。尽管最近已经报道了金属离子与核苷单磷酸之间二元和三元配合物的几种晶体结构，但尚未报道金属配合物与核苷二磷酸或三磷酸结合的结构。大多数二价金属离子催化磷酸从核苷多磷酸向各种受体的非酶促转移。因此，这些化合物在水溶液中在金属离子存在下会发生广泛水解，导致单磷酸的形成；例如，在pH 6.5时，Cu2+使ATP的水解加速约300倍（参考文献5）。我们在此报告通过单晶X射线分析确定的配合物[Zn(II)-H2ATP-2,2'-联吡啶]2.4H2O的晶体和分子结构。该配合物分子为ATP转运和磷酸基团转移机制提供了一种可能的模型。
