title: Calcyclin is a calcium and zinc binding protein.
abstract: Calcyclin, a cell cycle regulated protein, was recently purified from Ehrlich ascites tumour (EAT) cells and shown to be a calcium binding protein. Here we show that calcyclin monomer and dimer also bind zinc ions. Zinc binding sites seem to be different from calcium binding sites since: preincubation with Ca2+ lacks effect on the binding of Zn2+, and Ca2+ (but not Zn2+) increases tyrosine fluorescence intensity. Binding of Zn2+ reduces the extent of the conformational changes induced by Ca2+, and seems to affect Ca2(+)-binding. The data suggest that Ca2+ and Zn2+ might trigger the biological activity of calcyclin.
authors.affiliation: Nencki Institute of Experimental Biology, Warsaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Filipek
authors.forename: C W
authors.initials: CW
authors.lastname: Heizmann
authors.forename: J
authors.initials: J
authors.lastname: Kuźnicki
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002286:Carcinoma, Ehrlich Tumor; D002417:Cattle; D018797:Cell Cycle Proteins; D002851:Chromatography, High Pressure Liquid; D005453:Fluorescence; D015394:Molecular Structure; D011487:Protein Conformation; D051381:Rats; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; D014407:Tumor Cells, Cultured; D015032:Zinc / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D000075383:S100 Calcium Binding Protein A6; D009418:S100 Proteins; C489132:S100a6 protein, rat; D015032:Zinc; D002118:Calcium