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Circular dichroism studies on the zinc‐induced conformational changes in S‐100a and S‐100b proteins
Author(s) -
Mani Rajam S.,
Kay Cyril M.
Publication year - 1983
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 - 10.1016/0014-5793(83)80836-9
Subject(s) - circular dichroism , chemistry , zinc , tyrosine , conformational change , metal , crystallography , metal ions in aqueous solution , biophysics , stereochemistry , biochemistry , biology , organic chemistry
The effect of Zn 2+ binding on the circular dichroism (CD) spectra of brain‐specific S‐100a and S‐100b calcium‐binding proteins has been examined. In the presence of Zn 2+ , S‐100a undergoes a conformational change and the decrease in ellipticity at 222 nm, as a result of Zn 2+ addition, was nearly 1400 deg.cm −2 .dmol −1 , whereas with S‐100b there was no significant conformational change. Ca 2+ was able to bind to S‐100 proteins in the presence of Zn 2+ and the two metal‐ion binding sites on the proteins appear to be different. In the presence of Zn 2+ , K + had not significant effect on the conformation of S‐100 proteins. Ca 2+ and Zn 2+ binding induce different environments around the tyrosine residues in S‐100a, whereas with S‐100b, similar changes were observed for the single tyrosine residue, using either metal.