Fig. 4
Target-selective protein labelling with LDNASA chemistry. a Western blotting analysis of FKBP12 labelling in cell lysates. HeLa cell lysate was mixed with recombinant FKBP12 (1 µM) and incubated with reagent in 50 mM HEPES buffer, pH 7.2, 37 °C, 1 h. SAv-HRP, streptavidin–horseradish peroxidase conjugate; CBB, Coomassie brilliant blue staining. The high background (smear) signals of lane 6 and 7 may suggest unspecific labelling due to a high concentration of reagent (20 µM), whereas such background signals were less in lanes 1–5 (1–5 µM of reagent). b Western blotting analysis of endogenous FKBP12 labelling in live C2C12 cells. The cells were treated with 1 or 5 (1 µM) for 0–120 min at 37 °C in medium. c Time course plot of the endogenous FKBP12 labelling with 1. d Molecular structures of LDNASA 9 and LDAI 10 for FR labelling. e In-gel fluorescence and western blotting analysis of endogenous FR labelling in KB cells. The cells were treated with 9 or 10 (1 µM) for 0–60 min at 37 °C in medium. FA, Folic acid (competitive inhibitor). f Time profile of the endogenous FR labelling with 9. I and I30 min are band intensities of Oregon Green-labelled FR at the indicated time point and at 30 min, respectively. Error bars represent s.d., n = 3
