title: Crystallization and preliminary X-ray analysis of human carbonic anhydrase III.
abstract: Carbonic anhydrases catalyze the interconversion of carbon dioxide to bicarbonate. Human carbonic anhydrase isozyme III with a C-terminal hexahistidine tag was overexpressed in Eschericha coli, purified and crystallized. Diffraction data (93.4% completeness) were collected to 2.2 A resolution on an in-house R-AXIS IV++ image-plate system with Osmic mirrors and a Rigaku HU-H3R CU rotating-anode generator operating at 50 kV and 100 mA. A 60 degrees sweep of data were collected from a single crystal with a crystal-to-detector distance of 150 mm and a 0.5 degrees oscillation angle per frame using an exposure of 60 s per frame at 293 K. The crystals were shown to conform to the Laue hexagonal crystal system P6, with unit-cell parameters a = 44.7, c = 222.5 A and a scaling R(sym) of 0.087 for 11 962 unique reflections. Using the known crystal structure of the rat form of carbonic anhydrase isozyme III, a molecular-replacement model was built. This model was used for rotation and translation searches and uniquely defined the space group as P6(5). Rigid-body refinement of the model was used to generate an initial phased electron-density map with an R(work) of 31.17%.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA.
authors.forename: David M
authors.initials: DM
authors.lastname: Duda
authors.forename: Craig
authors.initials: C
authors.lastname: Yoshioka
authors.forename: Lakshmanan
authors.initials: L
authors.lastname: Govindasamy
authors.forename: Haiqian
authors.initials: H
authors.lastname: An
authors.forename: Chingkuang
authors.initials: C
authors.lastname: Tu
authors.forename: David N
authors.initials: DN
authors.lastname: Silverman
authors.forename: Robert
authors.initials: R
authors.lastname: McKenna
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D024402:Carbonic Anhydrase II / Q000737:chemistry; D024403:Carbonic Anhydrase III / Q000737:chemistry* / Q000235:genetics; D018360:Crystallography, X-Ray; D004926:Escherichia coli; D006801:Humans; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D024402:Carbonic Anhydrase II; D024403:Carbonic Anhydrase III