title: Crystallization and preliminary X-ray investigation of the recombinant Trypanosoma brucei rhodesiense calmodulin.
abstract: Bipyramidal crystals of the recombinant calmodulin from Trypanosoma brucei rhodesiense were obtained by vapor diffusion against 55% (v/v) 2-methyl-2,4-pentanediol in 0.05 M cacodylate buffer, pH 5.6. When few nucleation events occurred, crystals grew to 0.25 x 0.25 x 1.20 mm. The space group of the crystal is I4(1)22, with unit cell dimensions a = b = 56.88 A, c = 230.11 A, alpha = beta = gamma = 90 degrees, z = 16. The molecular mass and volume of the unit cell suggest that there is one molecule in the asymmetric unit. The I/sigma (I) ratio for data at 3.0 A resolution was 3.67, indicating that the final structure can be refined at higher resolution. Molecular replacement methods and the PC-refinement technique have not yet yielded the structure under a variety of search conditions. We are currently investigating the multiple isomorphous replacement approach to determine this crystal structure.
authors.affiliation: Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: el-Sayed
authors.forename: P C
authors.initials: PC
authors.lastname: Harkins
authors.forename: R O
authors.initials: RO
authors.lastname: Fox
authors.forename: K
authors.initials: K
authors.lastname: Anderson
authors.forename: C L
authors.initials: CL
authors.lastname: Patton
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002147:Calmodulin / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D003460:Crystallization; D018360:Crystallography, X-Ray; D004591:Electrophoresis, Polyacrylamide Gel; D011994:Recombinant Proteins / Q000737:chemistry; D016833:Trypanosoma brucei rhodesiense / Q000737:chemistry*
chemical_list: D002147:Calmodulin; D011994:Recombinant Proteins; D002118:Calcium