Retention of conformational entropy upon calmodulin binding to target peptides is driven by transient salt bridges.

ABSTRACT: Calmodulin (CaM) is a highly flexible calcium-binding protein that mediates signal transduction through an ability to differentially bind to highly variable binding sequences in target proteins. To identify how binding affects CaM motions, and its relationship to conformational entropy and target peptide sequence, we have employed fully atomistic, explicit solvent molecular dynamics simulations of unbound CaM and CaM bound to five different target peptides. The calculated CaM conformational binding entropies correlate with experimentally derived conformational entropies with a correlation coefficient R(2) of 0.95. Selected side-chain interactions with target peptides restrain interhelical loop motions, acting to tune the conformational entropy of the bound complex via widely distributed Ca

SUBMITTER: Smith DM 

PROVIDER: S-EPMC3471477 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature