Optical Control of Translation with a Puromycin Photoswitch.

Translation is an elementary cellular process that involves a large number of factors interacting in a concerted fashion with the ribosome. Numerous natural products have emerged that interfere with the ribosomal function, such as puromycin, which mimics an aminoacyl tRNA and causes premature chain termination. Here, we introduce a photoswitchable version of puromycin that, in effect, puts translation under optical control. Our compound, termed , features a diazocine that allows for reversible and nearly quantitative isomerization and pharmacological modulation. Its synthesis involves a new photoswitchable amino acid building block. shows little activity in the dark and becomes substantially more active and cytotoxic, in a graded fashion, upon irradiation with various wavelengths of visible light. In vitro translation assays confirm that inhibits translation with a mechanism similar to that of puromycin itself. Once incorporated into nascent proteins, reacts with standard puromycin antibodies, which allows for tracking protein synthesis using western blots and immunohistochemistry. As a cell-permeable small molecule, can be used for nascent proteome profiling in a variety of cell types, including primary mouse neurons. We envision as a useful biochemical tool for the optical control of translation and for monitoring newly synthesized proteins in defined locations and at precise time points.