title: Expression, purification, crystallization and preliminary X-ray diffraction analysis of the DDX3 RNA helicase domain.
abstract: DDX3 is a human RNA helicase that is involved in RNA processing and important human diseases. This enzyme belongs to the DEAD-box protein family, the members of which are characterized by the presence of nine conserved motifs including the Asp-Glu-Ala-Asp motif that defines the family. DDX3 has two distinct domains: an ATP-binding domain in the central region of the protein and a helicase domain in the carboxy-terminal region. The helicase domain of DDX3 was cloned and overexpressed in Escherichia coli. Crystallization experiments yielded crystals that were suitable for X-ray diffraction analysis. The final crystallization conditions were a reservoir solution consisting of 2 M ammonium sulfate, 0.1 M imidazole pH 6.4 plus 5 mM spermine tetrahydrochloride and a protein solution containing 10 mM HEPES, 500 mM ammonium sulfate pH 8.0. The crystals of the helicase domain belong to the monoclinic space group P2(1), with unit-cell parameters a = 43.85, b = 60.72, c = 88.39 A, alpha = gamma = 90, beta = 101.02 degrees , and contained three molecules per asymmetric unit. These crystals diffracted to a resolution limit of 2.2 A using synchrotron radiation at the European Synchrotron Radiation Facility (ESRF) and the Swiss Light Source (SLS).
authors.affiliation: Structural Biology and Biocomputing Programme, Spanish National Cancer Centre (CNIO) Macromolecular Crystallography Group, c/Melchor Fdez Almagro 3, 28029 Madrid, Spain.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Rodamilans
authors.forename: Guillermo
authors.initials: G
authors.lastname: Montoya
mesh_terms: D003001:Cloning, Molecular; D003460:Crystallization; D018360:Crystallography, X-Ray; D053487:DEAD-box RNA Helicases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D018076:DNA, Complementary; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D016133:Polymerase Chain Reaction; D011487:Protein Conformation
chemical_list: D018076:DNA, Complementary; C119332:DDX3X protein, human; D053487:DEAD-box RNA Helicases