Expression and Purification of Calmodulin for NMR and Other Biophysical Applications.

Calmodulin (CaM) is a ubiquitous calcium-sensing protein that has one of the most highly conserved sequences among eukaryotes. CaM has been a useful tool for biologists studying calcium signaling for decades. In recent years, CaM has also been implicated in numerous cancer-associated pathways, and rare CaM mutations have been identified as a cause of human cardiac arrhythmias. Here, we present a collection of our most recent and effective protocols for the expression and purification of recombinant CaM from Escherichia coli, including various isotopic labeling schemes, primarily for nuclear magnetic resonance (NMR) spectroscopy and other biophysical applications.