Genetically Engineered Calmodulin Self-Assembled on Gold Surface

Abstract

In order to construct intelligent materials consisting of functional proteins, the assembling techniques of proteins with retaining their functions even on a solid surfaces are required. Calmodulin, which expresses modulating function by conformation change with calcium binding, was selected as a model protein for molecular assembling. Calmodulin was genetically engineered for self-assembling on the gold surface with an oriented manner by introducing cysteine residues at the N-terminus of calmodulin. The engineered calmodulin retained Ca2+-responsive modulating function of enzyme activity as native calmodulin. Enzyme immunoassay and quartz crystal microbalance revealed that the engineered calmodulin was efficiently assembled on the gold surface in an acidic buffer solution as compared with native calmodulin. Genetic engineering is discussed to be effective on modifying proteins to be self-assembled on solid matrices.