Sigrell J A, Cameron A D, Jones T A, Mowbray S L
Department of Molecular Biology, Uppsala University, Sweden.
Protein Sci. 1997 Nov;6(11):2474-6. doi: 10.1002/pro.5560061124.
Ribokinase phosphorylates ribose to form ribose-5-phosphate in the presence of ATP and magnesium. The phosphorylated sugar can enter the pentose phosphate pathway or be used for the synthesis of nucleotides, histidine, and tryptophan. Ribokinase belongs to the PfkB family of carbohydrate kinases, for which no three-dimensional structure is currently known. We describe an improved purification protocol for Escherichia coli ribokinase and give evidence from light-scattering and gel filtration studies that the protein forms a dimer in solution. Several types of crystals are also described that have been obtained of apo ribokinase, ribokinase in the presence of ATP, and in a ternary complex with an ATP-analogue and ribose. The latter crystals give the best X-ray diffraction. A complete data set has been collected at the synchrotron source in Hamburg, to 2.6 A resolution using a frozen crystal. The crystals belong to space group P6(1)22 or P6(5)22 with cell parameters a = b = 95 A and c = 155 A.
在ATP和镁存在的情况下，核糖激酶将核糖磷酸化形成5-磷酸核糖。磷酸化的糖可以进入磷酸戊糖途径，或用于合成核苷酸、组氨酸和色氨酸。核糖激酶属于碳水化合物激酶的PfkB家族，目前其三维结构尚不清楚。我们描述了一种改进的大肠杆菌核糖激酶纯化方案，并通过光散射和凝胶过滤研究证明该蛋白在溶液中形成二聚体。还描述了几种类型的晶体，分别是脱辅基核糖激酶晶体、存在ATP时的核糖激酶晶体，以及与ATP类似物和核糖形成的三元复合物晶体。后一种晶体给出了最佳的X射线衍射结果。使用冷冻晶体在汉堡的同步加速器源上收集了完整的数据集，分辨率达到2.6埃。这些晶体属于空间群P6(1)22或P6(5)22，晶胞参数a = b = 95埃，c = 155埃。
