CROSS-LINIKING METHODS

Disclosed are methods and kits for producing a conformationally constrained peptide, such as a helix constrained peptide, in a cell. In some cases, the methods comprise contacting a cell comprising an intracellularly-localised recombinant peptide with a cross-linker and culturing the cell in the presence of the cross-linker, wherein the cross-linker forms thioether cross-links with at least two derivatisable amino acids located at anchoring positions in the recombinant peptide. The methods and kits and cells find application, for example, in the identification of inhibitors that can be used to disrupt protein-protein interactions.