Hydrophobic Peptides Affect Binding of Calmodulin and Ca as Explored by H/D Amide Exchange and Mass Spectrometry.

ABSTRACT: Calmodulin (CaM), a ubiquitous intracellular sensor protein, binds Ca(2+) and interacts with various targets as part of signal transduction. Using hydrogen/deuterium exchange (H/DX) and a high resolution PLIMSTEX (Protein-Ligand Interactions by Mass Spectrometry, Titration, and H/D Exchange) protocol, we examined five different states of calmodulin: calcium-free, calcium-loaded, and three states of calcium-loaded in the presence of either melittin, mastoparan, or skeletal myosin light-chain kinase (MLCK). When CaM binds Ca(2+), the extent of HDX decreased, consistent with the protein becoming stabilized upon binding. Furthermore, Ca(2+)-saturated calmodulin exhibits increased protection when bound to the peptides, forming high affinity complexes. The protocol reveals significant changes in

SUBMITTER: Sperry JB 

PROVIDER: S-EPMC3134286 | biostudies-literature | 2011 Apr

REPOSITORIES: biostudies-literature