Divalent cation dependent conformations of brain calmodulin detected by 1H NMR.

The effects of the Ca2+, Mg2+, Zn2+, Cd2+, Hg2+ and Mn2+ on the conformation of calmodulin (CaM) have been tested by using 400 MHz 1H NMR. In the aromatic region of the spectrum of CaM with a one molar ratio of cation per CaM, Zn2+, Cd2+, Hg2+ and Mn2+ induced spectral changes which were very similar to those seen for Ca2+. However, the Mg2+-induced change was different. These results are consistent with our pharmacological findings on divalent cations.