Calcium and membrane-induced changes in the structure and dynamics of three helical hairpins in annexin B12

The helical hairpins on the convex face of the crystal structure of soluble annexins are proposed to mediate binding to membranes, though the mechanism is not defined. A site-directed spin labeling (SDSL) experimental approach is used to investigate Ca(super 2+) and membrane-induced structural and dynamic changes that occurred in the helical hairpins encompassing three of the four D and E helices of annexin B12.