title: Structural differences among subfamilies of EF-hand proteins--a view from the pseudo two-fold symmetry axis.
abstract: We have analyzed the conformations of EF-lobes, adjacent pairs of EF-hand domains, in a coordinate system based on the approximate two-fold (z) axis that relates the two EF-hands. Two parameters - dE(ø), the azimuthal angle between the y-axis and the projection of the offset vector to helix E onto the yz-plane, and δdF(ø), the difference angle between the two helices (F1 and F2) of odd and even domains--characterize the openness of a single EF-hand domain and of an EF-lobe, respectively. We describe and compare values of dE(ø) and of δdF(ø) for EF-hand proteins of five subfamilies--CTER, CPV, S100, PARV, CALP--in calci- and apo- forms, with and without bound target proteins. Each subfamily has characteristic changes associated with binding calcium and/or target proteins.
authors.affiliation: Department of Medical Life Science, Graduate School of Medical Life Science, Yokohama City University, Suehiro-cho 1-7-29, Tsurumi-Ku, Yokohama, 230-0045, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawasaki
authors.forename: Robert H
authors.initials: RH
authors.lastname: Kretsinger
mesh_terms: D019703:Calcineurin / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D002147:Calmodulin / Q000737:chemistry; D020832:EF Hand Motifs; D018994:Myosin Light Chains / Q000737:chemistry; D011487:Protein Conformation; D009418:S100 Proteins / Q000737:chemistry; D019209:Troponin C / Q000737:chemistry
chemical_list: D002135:Calcium-Binding Proteins; D002147:Calmodulin; D018994:Myosin Light Chains; D009418:S100 Proteins; D019209:Troponin C; D019703:Calcineurin
keywords: EF-hand; EF-lobe; calcium; evolution; function; structural comparison; symmetry