The three-dimensional structure of ricin at 2.8 A.
The three-dimensional structure of ricin at 2.8 A.
复制标题
DOI：
10.1016/s0021-9258(18)61201-3
复制
发表时间：
1987-04
期刊：
影响因子：
--
通讯作者：
W. Montfort;J. E. Villafranca;A. Monzingo;S. Ernst;B. Katzin;E. Rutenber;N. Xuong;R. Hamlin;J. Robertus
中科院分区：
文献类型：
--
作者：
W. Montfort;J. E. Villafranca;A. Monzingo;S. Ernst;B. Katzin;E. Rutenber;N. Xuong;R. Hamlin;J. Robertus
异源二聚体植物毒素蓖麻毒素的X射线晶体结构已被确定在2.8-A分辨率。A链酶是一种球状蛋白质，具有广泛的二级结构和一个合理突出的裂缝，被认为是活性位点。B链凝集素折叠成两个拓扑结构相似的结构域，每个结构域以浅裂缝结合乳糖。在每个位点中，谷氨酰胺残基与半乳糖的OH-4形成氢键，从而解释了结合的差向异构体特异性。A和B链之间的界面显示出一些疏水接触，其中脯氨酸和苯丙氨酸侧链起着突出的作用。
The x-ray crystallographic structure of the heterodimeric plant toxin ricin has been determined at 2.8-A resolution. The A chain enzyme is a globular protein with extensive secondary structure and a reasonably prominent cleft assumed to be the active site. The B chain lectin folds into two topologically similar domains, each binding lactose in a shallow cleft. In each site a glutamine residue forms a hydrogen bond to the OH-4 of galactose, accounting for the epimerimic specificity of binding. The interface between the A and B chains shows some hydrophobic contacts in which proline and phenylalanine side chains play a prominent role.