Site-Specific Incorporation of Quadricyclane into a Protein and Photocleavage of the Quadricyclane Ligation Adduct

Frederick M. Tomlin, Chelsea G. Gordon, Yisu Han, Taia S. Wu, Ellen M. Sletten, Carolyn R. Bertozzi

Index: 10.1016/j.bmc.2018.04.009

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Abstract

The quadricyclane (QC) ligation is a bioorthogonal reaction between a quadricyclane moiety and a nickel bis(dithiolene) derivative. Here we show that a QC amino acid can be incorporated into a protein site-specifically using the pyrrolysine-based genetic code expansion platform, and subsequently used for ligation chemistry. Additionally, we exploited the photolability of the QC ligation product to render the adduct cleavable with a handheld UV lamp. We further developed a protein purification method that involves QC ligation of biotin to a protein of interest, capture on streptavidin resin, and finally release using only UV light. The QC ligation thus brings novel chemical manipulations to the realm of bioorthogonal chemistry.