3-DIMENSIONAL STRUCTURE AT 5-A RESOLUTION OF CYTOSOLIC ASPARATATE TRANSAMINASE FROM CHICKEN HEART
3-DIMENSIONAL STRUCTURE AT 5-A RESOLUTION OF CYTOSOLIC ASPARATATE TRANSAMINASE FROM CHICKEN HEART
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DOI：
10.1016/0022-2836(78)90403-5
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发表时间：
1978-01-01
影响因子：
5.6
通讯作者：
BRAUNSTEIN, AE
中科院分区：
文献类型：
--
作者：
BORISOV, VV;BORISOVA, SN;BRAUNSTEIN, AE
用x射线对鸡心脏胞质天冬氨酸转氨酶[EC 2.6.1.1]的正交晶体进行了研究。决议。晶体属于空间群P212121，晶胞尺寸a = 62.7 . ang。， b = 118.1 . ang。， c = 124.5 .ANG.…以5个重原子衍生物为基础计算电子密度图。从这张图谱中得到的分子模型清楚地揭示了由非晶体二偶体相关的2个相似结构的亚基。该蛋白的二级结构包括每个亚基9个螺旋片段。该酶在晶体形态下具有催化活性。从晶体中移除辅酶使得从不同的傅立叶图中得出酶分子中活性位点的位置成为可能。观察到伴随酶反应中间产物相互转化的显著构象变化。
An X-ray study of orthorhombic crystals of cytosolic aspartate transaminase [EC 2.6.1.1] from chicken heart was carried out at 5 .ANG. resolution. The crystals belong to space group P212121, with unit cell dimensions a = 62.7 .ANG., b = 118.1 .ANG., c = 124.5 .ANG.. The electron density map was calculated on the basis of 5 heavy-atom derivatives. The model of the molecule derived from this map revealed clearly 2 subunits of similar structure related by a non-crystallographic dyad. The secondary structure of the protein comprises 9 helical segments per subunit. The enzyme was catalytically active in the crystal form. Bemoval of the coenzyme from the crystals made it possible to derive from the difference Fourier map the position of the active site in the enzyme molecule. Significant conformational changes were observed which accompany the interconversion of intermediates of the enzymic reaction.