title: Ca(2+)-binding domain VI of rat calpain is a homodimer in solution: hydrodynamic, crystallization and preliminary X-ray diffraction studies.
abstract: The 21-kDa calcium-binding domain (VI) of the small subunit of rat calpain II has been expressed in Escherichia coli, purified, and crystallized. Two orthorhombic crystal forms have been obtained: space group P2(1)2(1)2(1) with a = 50.3, b = 56.5, c = 141.3 A; and space group C222(1) with a = 69.4, b = 73.9, c = 157.4 A. Diffraction data have been collected to 2.4 A. Sedimentation equilibrium, dynamic light scattering, and gel-permeation chromatography indicate that domain VI exists as a homodimer in solution. In accordance with the protein's behavior in solution, each crystal form contains two molecules per asymmetric unit. Screening for heavy-atom derivatives is in progress. To decrease the sensitivity to mercurials and to aid in the search for useful derivatives, Cys-to-Ser mutants have been prepared, expressed, and crystallized.
authors.affiliation: Biotechnology Research Institute, NRC, Montreal, Quebec, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Blanchard
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: M
authors.initials: M
authors.lastname: Cygler
authors.forename: C M
authors.initials: CM
authors.lastname: Kay
authors.forename: J
authors.initials: J
authors.lastname: Simon
authors.forename: C
authors.initials: C
authors.lastname: Arthur
authors.forename: P L
authors.initials: PL
authors.lastname: Davies
authors.forename: J S
authors.initials: JS
authors.lastname: Elce
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000737:chemistry; D002154:Calpain / Q000737:chemistry* / Q000235:genetics; D002850:Chromatography, Gel; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D008970:Molecular Weight; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D012542:Scattering, Radiation; D014461:Ultracentrifugation
chemical_list: D002135:Calcium-Binding Proteins; D011994:Recombinant Proteins; D002154:Calpain