Calmodulin in Action

Science Signaling  03 Feb 2009:
Vol. 2, Issue 56, pp. ec39
DOI: 10.1126/scisignal.256ec39

The ability to apply force to single molecules has allowed the controlled investigation of protein energy landscapes. However, limits in resolution have meant that studies have mainly been carried out at nonequilibrium, so that only unfolding and unbinding reactions could be investigated. Now Junker et al. (see the Perspective by Best and Hummer) have used a custom-built low-drift atomic force microscope to observe directly fluctuations of single calmodulin molecules under equilibrium conditions in the presence of Ca2+ and target peptides. The results show how ligand binding modulates the folding dynamics of calmodulin.

J. P. Junker, F. Ziegler, M. Rief, Ligand-dependent equilibrium fluctuations of single calmodulin molecules. Science 323, 633–637 (2009). [Abstract] [Full Text]

R. B. Best, G. Hummer, Unfolding the secrets of calmodulin. Science 323, 593–594 (2009). [Summary] [Full Text]