In Silico Design of Short Peptides as Sensing Elements for Phenolic Compounds

We have exploited a recently developed computational approach [Gladich et al., J. Chem. Phys. B 2015; DOI: 10.1021/acs.jpcb.5b06227] to design cyclic peptides capable of recognizing chlorogenic acid and related phenolic compounds. A peptide designed by this procedure was synthesized and characterized by circular dichroism and fluorescence spectroscopy, cyclic voltammetry, and differential pulse voltammetry. We found that the peptide is selective for chlorogenic acid against other ortho-diphenols, such as caffeic acid, and monophenols such as ferulic and coumaric acid. Indeed, when chlorogenic or caffeic acid are bound to the cyclic peptide, the ortho-diphenol moiety capable of undergoing oxidation is not available to the electrode surface due to diffusion limitation and steric hindrance. This phenomenon did not occur for cumaric and ferulic acid possibly because of limited complex formation with the cyclic peptide. In an electrochemical sensing system the peptide can therefore discriminate ortho-diphenols in a mixture of phenols.