X-ray structure of the ternary complex Zn(II)-ATP-2,2′-bipyridyl and possible model for ATP transport
X-ray structure of the ternary complex Zn(II)-ATP-2,2′-bipyridyl and possible model for ATP transport
复制标题
三元配合物 Zn(II)-ATP-2,2-联吡啶的 X 射线结构和 ATP 运输的可能模型
作者：
Pier Luigi Orioli;R. Cini;Donato Donati;Stefano Mangani
金属离子，核苷酸和芳香杂环胺之间的三元配合物正在研究通过X-射线衍射作为酶-金属-底物相互作用的可能模型1，2。肯纳德及其同事3报道了ATP二钠盐的晶体结构。虽然最近已经报道了金属离子和核苷一磷酸之间的二元和三元络合物的几种晶体结构，但是还没有报道将金属络合物与核苷二磷酸或核苷三磷酸结合的结构。大多数二价金属离子催化磷酸从核苷多磷酸到各种受体的非酶转移4。因此，这些化合物在水溶液中在金属离子的存在下进行广泛的水解，导致单磷酸盐的形成;例如，在pH 6.5时，Cu 2+加速ATP的水解约300倍（参考文献5）。本文报道了配合物[Zn（II）-H_2ATP-2，2 ′-bipyridine]_2·4H_2O的晶体结构和分子结构。该复合物分子为ATP转运和磷酸基团转移机制提供了一个可能的模型。
Ternary complexes between metal ions, nucleotides and aromatic heterocyclic amines are being investigated by X-ray diffraction as possible models for enzyme–metal–substrate interactions1,2. Kennard and coworkers3 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 acceptors4. 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.