title: Selective metal ion binding at the calcium-binding sites of the sea urchin extraembryonic coat protein hyalin.
abstract: The interaction of metal ions with the sea urchin extraembryonic coat protein hyalin was investigated. Hyalin, immobilized on nitrocellulose membrane, bound Ca2+ and this interaction was disrupted by ruthenium red and selective metal ions. The divalent cations Cd2+ and Mn2+, when present at a concentration of 30 microM, displaced hyalin-bound Ca2+. In competition assays, 1 mM Cd2+ or 3 mM Mn2+ were effective competitors with Ca2+ for binding to hyalin. Cobalt, at a concentration of 30 microM, was unable to displace protein-bound Ca2+, but was effective in competition assays at a concentration of at least 10 mM. Magnesium and the monovalent cation Cs+ were unable to disrupt Ca2(+)-hyalin interaction. Interestingly, Cd2+, Mn2+, and Co2+ mimicked the biological effects of Ca2+ on the hyalin self-association reaction. These results clearly demonstrate that the Ca2(+)-binding sites on hyalin can selectively accommodate other divalent cations in a biologically active configuration.
authors: Department of Biochemistry, Memorial University of Newfoundland, St. John's, Canada.
authors: J J
authors: JJ
authors: Robinson
mesh_terms: D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism*; D002132:Calcium Radioisotopes; D006818:Hyalin / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D011485:Protein Binding; D012617:Sea Urchins / Q000196:embryology* / Q000378:metabolism
chemical_list: D002132:Calcium Radioisotopes; D008670:Metals; D002118:Calcium