title: Cloning, expression, purification, crystallization and preliminary crystallographic analysis of selenomethionine-labelled KaiC-like protein PH0186 from Pyrococcus horikoshii OT3.
abstract: KaiC is the central protein in the circadian-clock system of cyanobacteria. A selenomethionine-labelled KaiC-homologous protein from Pyrococcus horikoshii OT3 (PH0186; 28 kDa) was crystallized by the sitting-drop vapour-diffusion method using ethanol as a precipitant. The crystals diffracted X-rays to beyond 2.0 A resolution using a synchrotron-radiation source. The space group of the crystals was determined to be C2, with unit-cell parameters a = 173.7, b = 51.8, c = 97.5 A, beta = 122.8 degrees. The crystal contains three molecules in the asymmetric unit (V(M) = 2.2 A(3) Da(-1)) and has a solvent content of 43.5%. Sixfold noncrystallographic symmetry was identified from self-rotation calculations, assuming the presence of a hexamer in the crystal.
authors.affiliation: Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Hua
authors.initials: H
authors.lastname: Ming
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Miyazono
authors.forename: Masaru
authors.initials: M
authors.lastname: Tanokura
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D011487:Protein Conformation; D043902:Pyrococcus horikoshii / Q000737:chemistry*; D012645:Selenomethionine / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D012645:Selenomethionine