title: Structure of a calpain Ca(2+)-binding domain reveals a novel EF-hand and Ca(2+)-induced conformational changes.
abstract: The crystal structure of a Ca(2+)-binding domain (dVI) of rat m-calpain has been determined at 2.3 A resolution, both with and without bound Ca2+. The structures reveal a unique fold incorporating five EF-hand motifs per monomer, three of which bind calcium at physiological calcium concentrations, with one showing a novel EF-hand coordination pattern. This investigation gives us a first view of the calcium-induced conformational changes, and consequently an insight into the mechanism of calcium induced activation in calpain. The crystal structures reveal a dVI homodimer which provides a preliminary model for the subunit dimerization in calpain.
authors.affiliation: Biotechnology Research Institute, NRC, Montréal, Québec, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Blanchard
authors.forename: P
authors.initials: P
authors.lastname: Grochulski
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: J S
authors.initials: JS
authors.lastname: Arthur
authors.forename: P L
authors.initials: PL
authors.lastname: Davies
authors.forename: J S
authors.initials: JS
authors.lastname: Elce
authors.forename: M
authors.initials: M
authors.lastname: Cygler
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000737:chemistry / Q000378:metabolism*; D002154:Calpain / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D019281:Dimerization; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D051381:Rats; D017386:Sequence Homology, Amino Acid
chemical_list: D002154:Calpain; D002118:Calcium