title: Comparative analysis of space-grown and earth-grown crystals of an aminoacyl-tRNA synthetase: space-grown crystals are more useful for structural determination.
abstract: Protein crystallization under microgravity aims at benefiting from the quasi-absence of convection and sedimentation to favor well ordered crystal nucleation and growth. The dimeric multidomain enzyme aspartyl-tRNA synthetase from Thermus thermophilus has been crystallized within dialysis reactors of the Advanced Protein Crystallization Facility in the laboratory on earth and under microgravity aboard the US Space Shuttle. A strictly comparative crystallographic analysis reveals that the crystals grown in space are superior in every respect to control crystals prepared in otherwise identical conditions on earth. They diffract X-rays more intensely and have a lower mosaicity, facilitating the process of protein structure determination. Indeed, the electron-density map calculated from diffraction data of space-grown crystals contains considerably more detail. The resulting three-dimensional structure model at 2.0 A resolution is more accurate than that produced in parallel using the data originating from earth-grown crystals. The major differences between the structures, including the better defined amino-acid side chains and the higher order of bound water molecules, are emphasized.
authors.affiliation: Département Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 Rue René Descartes, F-67084 Strasbourg CEDEX, France.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Ng
authors.forename: Claude
authors.initials: C
authors.lastname: Sauter
authors.forename: Bernard
authors.initials: B
authors.lastname: Lorber
authors.forename: Natalie
authors.initials: N
authors.lastname: Kirkland
authors.forename: John
authors.initials: J
authors.lastname: Arnez
authors.forename: Richard
authors.initials: R
authors.lastname: Giegé
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000737:chemistry*; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D016963:Thermus thermophilus / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014893:Weightlessness
chemical_list: D014867:Water; D000604:Amino Acyl-tRNA Synthetases