人类的核苷二磷酸激酶的晶体结构,NM23-H2。
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韦伯PA, Perisic O, Mendola CE、支持者JM,威廉姆斯RL
人类的核苷二磷酸激酶的晶体结构,NM23-H2。
J杂志。1995年8月25日,251 (4):574 - 87。
- PubMed ID
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7658474 (在PubMed]
- 文摘
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NM23-H2的分辨率2.8 x射线结构决定了分子替换使用的结构Myxococcus克桑托斯核苷二磷酸激酶(民主党)。NM23-H2是一种人类NDP激酶。酶催化作用磷酰基转移,结合DNA,可以在体外激活原癌基因致癌基因的转录。NM23也被报道的抑制在某些类型的肿瘤转移。而m .克桑托斯民主党激酶是四聚物,NM23-H2六聚体。NM23-H2的褶皱是相同的其他民主党激酶的褶皱。两个反平行的螺旋加入了一种把一个核苷酸绑定裂的边缘。这个地区移动hinge-like的方式以应对衬底绑定和水晶包装部队。额外的构象的差异民族民主党激酶地区主要是参与蛋白质寡聚物接触。唯一保守蛋白质间交互作用在所有民主党激酶是一种二聚的交互。 Several mutations of NM23-H2 have been detected in tumour tissues. These mutations do not involve residues interacting with the substrates, and probably destabilise the enzyme without directly affecting the catalytic activity. Low level phosphorylation of serines has been reported for NM23 both in vitro and in vivo. The structure of the hexamer indicates that two serine residues that have been reported as being phosphorylated, Ser44 and Ser122, are on the surface of the hexamer, and are likely to be phosphorylated by exogenous kinases. In contrast, Ser120 is buried, and is most likely phosphorylated by a direct transfer from the phosphohistidine intermediate of the reaction mechanism.