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. Author manuscript; available in PMC: 2020 Jan 22.
Published in final edited form as: Nature. 2019 Jul 22;572(7769):387–391. doi: 10.1038/s41586-019-1439-1

Extended Data Fig. 1. Determination of the modification rate on E860 of SdeA.

Extended Data Fig. 1

a. Peak areas of the extracted-ion chromatograms (XIC) were normalized based on the area of the unmodified peptide -I608IQQILANPDCIHDDHVLINGQK630−. The occupancy rate of glutamylation on residue was calculated based on the consumption of the unmodified -H855GEGTESEFSVYLPEDVALVPVK877− in samples from cells cotransfected to express GFP-SidJ compared to those of controls from cells transfected to express GFP.

b. SidJ induces a 258.09 Dalton post-translation modification on E860 within the mART motif of SdeA. 4xFlag-mART purified from HEK293T cells coexpressing SidJ detected by silver staining (Fig. 2d) was analyzed by mass spectrometric analysis. Tandem mass (MS/MS) spectrum shows the fragmentation profile of the modified peptide -H855GEGTEGluGluSEFSVYLPEDVALVPVK877−, including ions b5 and b6 that confirms the modification site at the E860 residue. In each case, similar results were obtained in three independent experiments.