Sequence reversed peptide from CaMKK binds to calmodulin in reversible Ca2+ -dependent manner

Calmodulin (CaM) is a highly versatile Ca(2+) signaling transducer known to regulate over a hundred proteins. In this paper, we further demonstrate the versatility of CaM binding by showing that it binds to a synthetic peptide (revCKKp) made by reversing the amino acid sequence of the CaM-binding peptide (CKKp) from CaM-dependent protein kinase kinase (CaMKK) (residues 438-463). Sequence comparison between revCKKp and other CaM-binding peptides (CBPs) from the CaM target databank showed that revCKKp does not resemble any existing classes of CBPs, except CKKp M. Zhang, T. Yuan, Molecular mechanisms of calmodulin's functional versatility, Biochem. Cell Biol. 76 (1998) 313-323; S.W. Vetter, E. Leclerc, Novel aspects of calmodulin target recognition and activation, Eur. J. Biochem. 270 (2003) 404-414]. Furthermore, computational modeling showed that revCKKp could bind CaM in a similar manner to CKKp. Lastly, we experimentally showed that our synthetic revCKKp binds to CaM in a reversible Ca(2+)-dependent manner.