Fig. 2
From: Photocatalytic proximity labelling of MCL-1 by a BH3 ligand
Ligand-directed labelling of MCL-1 with fluorescent and biotinylated radical trapping agents. RTA: radical trapping agent. a Chemical structures of ligand-directed labelling reagent Ru(II)(bpy)3-NOXA-B 1, fluorescent label TAMRA-RTA 2, biotinylated label biotin-RTA 3 and minimal label Ac-RTA 4. b Fluorescence anisotropy competition experiments for the inhibition of the FITC-NOXA-B/MCL-1 interaction by Ru(II)(bpy)3-NOXA-B 1 (red) and Ac-NOXA-B 5 (black). Error bars represent the standard deviation of three repeats. IC50 values for peptides 1 and 5 obtained from these experiments are quoted ± SEM. c Fluorescence image (FL) and Coomassie Brilliant Blue (CBB) stained SDS-PAGE gels of photolabelled mixtures; fluorescence image shows labelling of MCL-1 using 1 min irradiation, 5 µM TAMRA-RTA 2, 1 µM Ru(II)(bpy)3-NOXA-B 1 and 10 µM APS; CBB stain shows MCL-1 for all conditions. Reactions were carried out on 5 µM MCL-1 in ammonium bicarbonate buffer, pH 7.4. Pictures of complete gels are shown in Supplementary Fig. 15. d Deconvoluted ESI-MS spectra of photolabelling reaction mixtures displaying fluorescently modified (18396 Da) and biotinylated MCL-1 (18209 Da). Star denotes possible oxidised protein species (see Supplementary Fig. 16 for annotated spectrum).
