Extended Data Fig. 3: Characterization of dual-modified trastuzumab Fab.
a, Structure of the sortase-reactive coumarin-glycine probe 20. b, Deconvoluted ESI-MS of unmodified (left) and modified (right) Fab after treatment of the sample with DTT to reduce the interchain disulfide bond (calc., calculated; obs, observed). Signals correspond to the light chain (LC, shown in grey), heavy chain (HC, shown in dark grey), and the coumarin- and rhodamine-modified products (light blue and red, respectively). c, Reducing SDS–PAGE analysis of the reaction over time, visualized by in-gel fluorescence to detect the presence of rhodamine from thioester 4 and coumarin from sortase probe 20, respectively, and by Coomassie stain. n = 3 independent experiments with similar results, representative data shown. Full gel images are available in the Source Data file.
