Oxidation-Induced Protein Cross-Linking in Mammalian Cells.

A proximity-enabled protein cross-linking strategy with additional spatiotemporal control is highly desirable. Here, we report an oxidation-induced protein cross-linking strategy involving the incorporation of a vinyl thioether group into proteins in both Escherichia coli and mammalian cells via genetic code expansion. We demonstrated that vinyl thioether can be selectively induced by exogenously added oxidant or by reactive oxygen species from the cellular environment, as well as by photocatalysts, and converted into a Michael acceptor, enabling fluorescence labeling and protein cross-linking.