title: Prokaryotic calcium-binding protein of the calmodulin superfamily. Calcium binding to a Saccharopolyspora erythraea 20 kDa protein.
abstract: The EF-hand calcium-binding protein from Saccharopolyspora erythraea has been shown, using 113Cd NMR, to possess three Cd(2+)-ion binding sites. This indicates that of the four EF-hand motifs in the molecule, one (probably site 2) is unable to bind Cd(2+)-ions. Data from the titration of the protein with Ca2+, in the presence of Quin2, were fitted to a curve calculated on the assumption that the protein contains three high affinity Ca2+ binding sites, two of which (pK1 = 8.0, pK2 = 9.0) are strongly cooperative, and one single site (pK3 = 7.5). Preliminary 1H NMR experiments indicate marked structural changes upon Ca(2+)-binding.
authors.affiliation: Physical Chemistry 2, University of Lund, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Bylsma
authors.forename: T
authors.initials: T
authors.lastname: Drakenberg
authors.forename: I
authors.initials: I
authors.lastname: Andersson
authors.forename: P F
authors.initials: PF
authors.lastname: Leadlay
authors.forename: S
authors.initials: S
authors.lastname: Forsén
mesh_terms: D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D002147:Calmodulin / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000145:classification / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D016930:Saccharopolyspora / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D002147:Calmodulin; D005656:Fungal Proteins; D002118:Calcium