Vijay-Kumar S, Kumar V D
Department of Biochemistry, Fels Institute for Cancer Research and Molecular Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA.
Nat Struct Biol. 1999 Jan;6(1):80-8. doi: 10.1038/4956.
The crystal structure of calcium-bound unmyristoylated bovine neurocalcin from Escherichia coli has been determined at 2.4 A resolution. The three-dimensional structure reveals a highly compact structure consisting of: (i) two pairs of calcium-binding EF-hands (EF1-EF2 and EF3-EF4); (ii) a calcium ion bound at EF2, EF3 and EF4 sites; and (iii) an EF1-hand that is disabled from calcium-binding due to a Cys-Pro sequence in the Ca2+-binding loop. The crystal structure of neurocalcin resembles photoreceptor recoverin in overall topology, however its EF2- and EF4-hands differ. Recently, neurocalcin in the calcium-bound state has been shown to stimulate mammalian rod outer segment membrane guanylate cyclase. A possible site for cyclase activity based on the three-dimensional structure is discussed.
已通过分辨率为2.4埃确定了来自大肠杆菌的钙结合未豆蔻酰化牛神经钙蛋白的晶体结构。三维结构揭示了一种高度紧凑的结构，其由以下部分组成：(i) 两对钙结合EF手结构域（EF1-EF2和EF3-EF4）；(ii) 一个结合在EF2、EF3和EF4位点的钙离子；以及(iii) 由于Ca2+结合环中的半胱氨酸-脯氨酸序列而无法结合钙的EF1手结构域。神经钙蛋白的晶体结构在整体拓扑结构上类似于光感受器恢复蛋白，然而其EF2和EF4手结构域有所不同。最近，已证明处于钙结合状态的神经钙蛋白可刺激哺乳动物视杆细胞外段膜鸟苷酸环化酶。基于三维结构讨论了环化酶活性的一个可能位点。
