Purification‐Free, Target‐Selective Immobilization of a Protein from Cell Lysates

Protein immobilization has been widely used for laboratory experiments and industrial processes. Preparation of a recombinant protein for immobilization usually requires laborious and expensive purification steps. Here, a novel purification‐free, target‐selective immobilization technique of a protein from cell lysates is reported. Purification steps are skipped by immobilizing a target protein containing a clickable non‐natural amino acid (p‐azidophenylalanine) in cell lysates onto alkyne‐functionalized solid supports via bioorthogonal azide‐alkyne cycloaddition. In order to achieve a target protein‐selective immobilization, p‐azidophenylalanine was introduced into an exogenous target protein, but not into endogenous non‐target proteins using host cells with amber codon‐free genomic DNAs. Immobilization of superfolder fluorescent protein (sfGFP) from cell lysates is as efficient as that of the purified sfGFP. Using two fluorescent proteins (sfGFP and mCherry), the authors also demonstrated that the target proteins are immobilized with a minimal immobilization of non‐target proteins (target‐selective immobilization).