Extended Data Fig. 5: Characterization of the bond formed between cGAS Y405 and E2 K159.

a, Magnified view of the E2 active site in cGAS-E2 complex showing continuous density between Y405 of cGAS and K159 of E2. b, Extracted ion chromatograms (left panel) and corresponding mass spectra of precursor ions (right panel) of the control peptide HPRPSEVKNER and the modified peptide HPRPSEVKNER bearing an NTFY remnant at K159 (red). MS signals of the control peptide were only detected in E2 but not cGAS or cGAS-E2 samples. In contrast, MS signals of the modified peptide were only detected in cGAS-E2 but not E2 or cGAS samples. All data are representative of three independent experiments.