title: Crystallization and preliminary characterization of the Thermus thermophilus RNA helicase Hera C-terminal domain.
abstract: 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.
authors.affiliation: Department of Molecular Structural Biology, Institute for Microbiology and Genetics, Georg-August-Universität, Göttingen, Germany.
authors.forename: Markus G
authors.initials: MG
authors.lastname: Rudolph
authors.forename: Julia G
authors.initials: JG
authors.lastname: Wittmann
authors.forename: Dagmar
authors.initials: D
authors.lastname: Klostermeier
mesh_terms: D000595:Amino Acid Sequence; D003460:Crystallization; D018360:Crystallography, X-Ray; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D020365:RNA Helicases / Q000737:chemistry*; D012643:Selenium; D016415:Sequence Alignment; D016963:Thermus thermophilus / Q000201:enzymology*
chemical_list: D020365:RNA Helicases; D012643:Selenium