Calcium-dependent folding of single calmodulin molecules.

ABSTRACT: Calmodulin is the primary calcium binding protein in living cells. Its function and structure depend strongly on calcium concentration. We used single molecule force spectroscopy by optical tweezers to study the folding of calmodulin in the physiologically relevant range. We find that full-length calmodulin switches from a rich and complex folding behavior at high calcium to a simple folding pathway at apo conditions. Using truncation mutants, we studied the individual domains separately. Folding and stability of the individual domains differ significantly at low calcium concentrations. With increasing calcium, the folding rate constants increase while unfolding rate constants decrease. The complete kinetic as well as energetic behavior of both domains could be modeled using a calcium-depe

SUBMITTER: Stigler J 

PROVIDER: S-EPMC3497792 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature