Calcium binding properties of beta-crystallins

beta-Crystallins, the oligomeric proteins of the eye lens, were found to bind calcium ions with low affinity, in the millimolar range. Calcium was found to induce conformational changes in the secondary and tertiary structure of beta-crystallins. While these changes in conformation are seen in low ionic strength media, they are masked when the protein is dissolved in an intermediate ionic strength medium, where oligomers of lower molecular weight are formed. The calcium binding takes place in these conditions. The behaviour of this protein with respect to calcium binding is reviewed.