Detection of Polypeptide Interactions Via Periodate Triggered Dopa Crosslinking

Protein-Protein interactions mediate most biological function, yet elucidation of the molecular architecture within a cell still remains a formidable challenge for molecular biologist. We have developed a novel, bioorthogonal cross-linking chemistry based upon periodate mediated oxidation of the artificial amino acid 3,4- Dihydroxyphenylalanine to a resultant ortho-quinone. This ortho-quinone was proven capable of capturing either cysteine, lysine, histidine, or a peptidyl alpha -amine in templated chemical reactions. After elucidating the chemistry, we describe utilization of this methodology to map peptide-protein interactions between the 26S proteasome and activation domains as well as the Arp 2/3 complex and the CA peptide. Finally, we present the creation of a chimeric molecule consisting of the biarsencial fluorescent reporter FLAsH conjugated to 3,4-Dihydroxyphenylalanine as a route to deliver 3,4-dihydroxyphenylalanine site specifically to a protein of interest and probe for protein-protein interactions partners in cell lysates.