Targeting translation activity at the ribosome interface with UV-active small molecules
Puromycin is a well-known antibiotic that is used to study the mechanism of protein synthesis and to monitor translation efficiency due to its incorporation into nascent peptide chains. However, puromycin effects outside the ribo-some catalytic core remain unexplored. Here, we developed two puromycin analogues (3PB and 3PC) that can efficiently interact with several proteins involved in translation, ribosome function and RNA processing. We biochemically characterized the binding of these analogues and globally mapped the direct small molecule-protein interactions in living cells using clickable and photoreactive puromycin-like probes in combination with in-depth mass spectrometry. We identified a list of proteins that interact with ribosomes during translation (e.g. eEF1A, ENO1 and GRP78) and we addressed possible uses of the probes to sense the activity of protein synthesis and to capture associated RNA. By coupling genome-wide RNA sequencing methods with these molecules, the characterization of unexplored translational control mechanisms will be feasible.