A cryptophane-based “turn-on” ¹²⁹Xe NMR biosensor for monitoring calmodulin

Abstract

We present the first cryptophane-based "turn-on" ¹²⁹Xe NMR biosensor, employing a peptide-functionalized cryptophane to monitor the activation of calmodulin (CaM) protein in solution. In the absence of CaM binding, interaction between the peptide and cryptophane completely suppresses the hyperpolarized ¹²⁹Xe-cryptophane NMR signal. Biosensor binding to Ca²⁺-activated CaM produces the expected ¹²⁹Xe-cryptophane NMR signal.