Electrochemical biosensors based on peptide-kinase interactions at the kinase docking site

Kinases are important cancer biomarkers and are conventionally detected based on their catalytic activity. Kinases regulate cellular activities by phosphorylation of motif-specific multiple substrate proteins, resulting in lack of selectivity of activity-based kinase biosensors. We present an alternative approach of sensing kinases based on the interactions of their allosteric docking sites with a specific partner protein. The new approach was demonstrated for the ERK2 kinase and its substrate ELK-1. A peptide derived from ELK-1 was bound to a gold electrode and ERK2 sensing was performed by electrochemical impedance spectroscopy. The sensors showed high level of target selectivity for ERK2 when compared with p38{gamma} kinase and BSA. ERK2 was detected in its cellular concentration range, 0.2-8.0 M. Using the flexibility of peptide design, our method is generic for developing sensitive and substrate-specific biosensors and other disease-related enzymes based on their interactions. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/468793v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@277550org.highwire.dtl.DTLVardef@870467org.highwire.dtl.DTLVardef@32098aorg.highwire.dtl.DTLVardef@1104840_HPS_FORMAT_FIGEXP M_FIG C_FIG