Extended Data Fig. 2: Biochemical fractionation and mass spectrometry identification of VACV poxin.
From: Viral and metazoan poxins are cGAMP-specific nucleases that restrict cGAS–STING signalling
a, Schematic of purification process developed to enrich VACV poxin from infected cell lysates. Lysates were fractionated using Q IEX and S200 size-exclusion chromatography (purification scheme 1, left) or ammonium sulfate precipitation followed by phenyl hydrophobic interaction and S75 size-exclusion chromatography (purification scheme 2, right). Fractions were tested for 2′,3′-cGAMP degradation activity at each stage of purification and active fractions were pooled for subsequent purification steps. Fractions with peak activity after size exclusion were analysed with mass spectrometry. Fold enrichment of proteins in the IEX active fraction compared to two inactive fractions was calculated using label-free mass spectrometry quantification. b, List of VACV proteins identified in each purification scheme. VACV poxin is encoded by the B2R gene (green).
