Crystal structure of common type acylphosphatase from bovine testis.
Crystal structure of common type acylphosphatase from bovine testis.
复制标题
牛睾丸普通型酰基磷酸酶的晶体结构。
DOI：
10.1016/s0969-2126(97)00167-6
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发表时间：
1997
期刊：
影响因子：
5.7
通讯作者：
Pär Nordlund
中科院分区：
文献类型：
--
作者：
M. Thunnissen;N. Taddei;G. Liguri;Giampietro Ramponi;Pär Nordlund
背景：酰基磷酸酶（ACP）是一种低分子量的磷酸单水解酶，具有高特异性的催化水解存在于酰基磷酸盐中的羧基-磷酸键。这种酶被认为调节代谢过程，其中涉及酰基磷酸盐，如糖酵解和核糖核苷酸的产生。此外，该酶能够水解在膜泵（Ca2++Mg2+） atp酶等作用过程中形成的磷-天冬氨酸中间体。虽然肌肉ACP的三级结构已经通过核磁共振光谱确定，但对ACP的催化机制知之甚少，进一步的结构可能会提供更多的了解。结果：用x射线晶体学测定了牛睾丸“普通型”ACP的结构，分辨率为1.8 Å。使用15到1.8之间的所有数据，该结构已被细化到R因子为17.0% Å。硫酸盐和氯离子在活性中心的结合可以详细描述该位点。普通型与肌ACP的整体蛋白折叠相似，但其环的构象却大不相同。在某种程度上，这些差异可能是由普通类型形式的活性部位的离子结合引起的。ACP的磷酸结合环与低分子量蛋白酪氨酸磷酸酶有显著的相似之处。结论：已经确定了ACP的活性位点，从而提出了一种反应机制，即与Arg23结合的磷酸段作为碱基，从与Asn41配体的亲核水分子中提取一个质子。过渡态中间体由磷酸盐结合环稳定。我们认为催化是底物辅助的，这可能解释了为什么这种酶只能水解酰基磷酸盐。
Background:Acylphosphatase (ACP) is a low molecular weight phosphomonohydrolase catalyzing with high specificity the hydrolysis of the carboxyl-phosphate bond present in acylphosphates. The enzyme is thought to regulate metabolic processes in which acylphosphates are involved, such as glycolysis and the production of ribonucleotides. Furthermore the enzyme is capable of hydrolyzing the phospho-aspartyl intermediate formed during the action of membrane pumps such as (Ca2++Mg2+) ATPase. Although the tertiary structure of a muscle ACP has been determined by NMR spectroscopy, little is known about the catalytic mechanism of ACP and further structures might provide an increased understanding.Results:The structure of ‘common type' ACP from bovine testis has been determined by X-ray crystallography to a resolution of 1.8 Å. The structure has been refined to an R factor of 17.0 % using all data between 15 and 1.8 Å. The binding of a sulphate and a chloride ion in the active centre allows a detailed description of this site. The overall protein folds of common type and muscle ACP are similar but their loops have very different conformations. These differences, in part, are probably caused by the binding of the ions in the active site of the common type form. The phosphate-binding loop of ACP shows some remarkable similarities to that of low molecular weight protein tyrosine phosphatase.Conclusions:The active site of ACP has been located, enabling a reaction mechanism to be suggested in which the phosphate moiety bound to Arg23 acts as a base, abstracting a proton from a nucleophilic water molecule liganded to Asn41. The transition-state intermediate is stabilized by the phosphate-binding loop. We suggest the catalysis to be substrate assisted, which probably explains why this enzyme can only hydrolyze acylphosphates.
共轭方向最小化：一种改进的大分子细化方法。
DOI：
10.1107/s0108767392005415
发表时间：
1992
期刊：
Acta crystallographica. Section A, Foundations of crystallography
影响因子：
--
作者：
Tronrud,DE
通讯作者：
Tronrud,DE