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Zinc binding reverses the calcium‐induced arachidonic acid‐binding capacity of the S100A8/A9 protein complex
Author(s) -
Kerkhoff Claus,
Vogl Thomas,
Nacken Wolfgang,
Sopalla Claudia,
Sorg Clemens
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(99)01322-8
Subject(s) - chemistry , s100a8 , calcium , arachidonic acid , s100a9 , calcium binding protein , binding site , plasma protein binding , biochemistry , divalent , zinc , binding protein , mole , ef hand , biophysics , enzyme , biology , organic chemistry , gene
Analysis of the calcium‐induced arachidonic acid (AA) binding to S100A8/A9 revealed that maximal AA binding was achieved at molar ratios of 1 mol S100A8 and 1 mol S100A9 and for values greater than 3 calciums per EF‐hand. The AA binding capacity was not induced by the binding of other bivalent cations, such as Zn 2+ , Cu 2+ , and Mg 2+ , to the protein complex. In contrast, the binding of AA was prevented by the addition of either Zn 2+ or Cu 2+ in the presence of calcium, whereas Mg 2+ failed to abrogate the AA binding capacity. The inhibitory effect was not due to blocking the formation of S100A8/A9 as demonstrated by a protein‐protein interaction assay. Fluorescence measurements gave evidence that both Zn 2+ and Cu 2+ induce different conformational changes thereby affecting the calcium‐induced formation of the AA binding pocket within the protein complex. Due to the fact that the inhibitory effect of Zn 2+ was present at physiological serum concentrations, it is assumed that released S100A8/A9 may carry AA at inflammatory lesions, but not within the blood compartment.