Rudolph Markus G, Wittmann Julia G, Klostermeier Dagmar
Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Georg-August-Universität, Göttingen, Germany.
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Mar 1;65(Pt 3):248-52. doi: 10.1107/S1744309108043145. Epub 2009 Feb 14.
Heat-resistant RNA-dependent ATPase (Hera) from Thermus thermophilus is a DEAD-box RNA helicase. Two constructs encompassing the second RecA-like domain and the C-terminal domain of Hera were overproduced in Escherichia coli and purified to homogeneity. Single crystals of both Hera constructs were obtained in three crystal forms. A tetragonal crystal form belonged to space group P4(1)2(1)2, with unit-cell parameters a = 65.5, c = 153.0 A, and contained one molecule per asymmetric unit. Two orthorhombic forms belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 62.8, b = 70.9, c = 102.3 A (form I) and a = 41.6, b = 67.6, c = 183.5 A (form II). Both orthorhombic forms contained two molecules per asymmetric unit. All crystals diffracted X-rays to beyond 3 A resolution, but the tetragonal data sets displayed high Wilson B values and high mean |E(2) - 1| values, indicating potential disorder and anisotropy. The tetragonal crystal was phased by MAD using a single selenium site.
嗜热栖热菌的耐热性RNA依赖性ATP酶（Hera）是一种DEAD盒RNA解旋酶。包含Hera第二个类RecA结构域和C端结构域的两种构建体在大肠杆菌中过量表达并纯化至均一。两种Hera构建体的单晶均以三种晶体形式获得。一种四方晶体形式属于空间群P4(1)2(1)2，晶胞参数a = 65.5，c = 153.0 Å，每个不对称单元包含一个分子。两种正交晶系形式属于空间群P2(1)2(1)2(1)，晶胞参数a = 62.8，b = 70.9，c = 102.3 Å（晶型I）和a = 41.6，b = 67.6，c = 183.5 Å（晶型II）。两种正交晶系形式每个不对称单元均包含两个分子。所有晶体的X射线衍射分辨率均超过3 Å，但四方数据集显示出较高的威尔逊B值和较高的平均|E(2) - 1|值，表明存在潜在的无序和各向异性。四方晶体通过使用单个硒位点的MAD法进行相位确定。
