Skip to main content
. 2018 Aug 13;14(8):e1007248. doi: 10.1371/journal.ppat.1007248

Fig 1. SseI deamidates an essential glutamine residue in the switch II region of Gαi2.

Fig 1

(A) Western blot analysis of Gαi2. GST-Gαi2 was coexpressed without (control) and with SseI in E. coli. Purified GST-Gαi2 was immunoblotted and detected by the Gαi2-specific antibody (Gαi2) and by the deamidation-specific antibody (GαQE). (B) Gαi2 coexpressed with SseI was analyzed by HPLC-MS/MS spectrometry. Combined extracted ion chromatograms for m/z 455.2(2+) and 455.7(2+), corresponding to the tryptic peptides MFDVGGQR and MFDVGGER (amino acids 199–206) of Gαi2, are shown (see also S1B and S1C Fig). (Upper panel) Gαi2 coexpressed with inactive SseI-C178A. (Lower panel) Gαi2 coexpressed with active wt SseI. (C) Immunoblot analysis of recombinantly expressed Gαi2 incubated with wild type C-terminal part of SseIC (wt) or with 3 different mutant SseIC (C178A, H216A and D231A).