The authors regret that in the original manuscript, position 128 in the EGFR was referred to incorrectly as L128, rather than N128. This error occurred on page 3237 in the following sentence: “To this end, EGFR was mutated to arry a TAG codon at the previously published labeling site, Leu 128, and cloned into a single expression vector that encodes the cognate pair of tRNAcua: tRNA-synthetase17,18 (Fig. S1a†).” The error also occurred in Fig. 1a, the corrected version of which is displayed below, along with the original, unaltered caption. These errors do not affect any of the experimental results and discussion or conclusions reported in the paper, only the display of the figure and text. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.