Photo‐crosslinking: An Emerging Chemical Tool for Investigating Molecular Networks in Live Cells

Abstract Studying protein–protein interactions (PPIs) is useful for understanding cellular functions and mechanisms. Evaluating these PPIs under conditions as similar as possible to native conditions can be achieved using photo‐crosslinking methods because of their on‐demand ability to generate reactive species in situ by irradiation with UV light. Various fusion tag, metabolic incorporation, and amber codon suppression approaches using various crosslinkers containing aryl azide, benzophenone, and diazirines have been applied in live cells. Mass spectrometry and immunological techniques are used to identify crosslinked proteins based on their capture transient and context‐dependent interactions. Herein we discuss various incorporation methods and crosslinkers that have been used for interactome mapping in live cells.