Extended Data Fig. 9: Phylogenetic and biochemical analysis of SECφ4 Exo.
From: A DNA-gated molecular guard controls bacterial Hailong anti-phage defence
a, Phylogenetic analysis of ~1,700 SECφ4 Exo sequence homologs obtained using NCBI BLAST. b, Genera of phages encoding SECφ4 Exo. c, SECφ4 gp43 DNA exonuclease (Exo) was expressed as an N-terminal 6xHis-SUMO2 fusion and purified by Ni-NTA and separated by size exclusion chromatography. d, Coomassie-stained SDS-PAGE analysis of fully purified SECφ4 Exo. e, Analysis of 5 nt fluorescein-labeled deoxynucleotide substrates (F-dA, dA-F, dC-F), 5 nt single-stranded RNA (rA-F), or 20 bp thymidine-labeled double-stranded DNA (dA-dT-F). Direction of fluorescein (labeled as green F) tagged to the oligonucleotide indicates either a 5′-tagged DNA (indicating a free 3′ end) or a 3′-tagged DNA (indicating a free 5′ end). Data shown are representative of at least three independent experiments. f, AlphaFold modeled structure of SECφ4 Exo with escape mutant residues within scaffolding regions.
