Extended Data Fig. 1: SEE-CITE photoaffinity labeling (PAL).

A, Established PAL probes generate molecule-of-interest (MOI)-dependent modification of proteins, which can fragment in unanticipated ways, resulting in complex data analysis and lower coverage, particularly for large molecules. B, In SEE-CITE, MOIs are connected to diazirine handle 1 via a silyl ether linkage, which allows for straightforward removal of bulky molecules of interest (MOIs) from labeled peptides. C, As all SEE-CITE peptide modifications are the same mass, independent of the MOI mass, the relative labeling of different probes can be compared using isotopically enriched biotin-azide capture reagents, which provides a quantitative measure of structure-activity relationships (SAR) at specific binding sites identified.