Extended Data Fig. 1: PARIS is an antiphage toxin-antitoxin system.
From: Architecture and activation mechanism of the bacterial PARIS defence system
a, Schematic representation of the domains in the E. coli B185 AriA and AriB subunits, with predicted domain annotations. b, Multiple sequence alignment showing conservation of amino acid residues involved in ATP binding and catalysis in AriA and Rad50 homologues. The conserved residues involved in catalysis are indicated. c, ATPase activity of AriA and its conserved residue mutants. K39I: a Walker-A motif mutant designed to disrupt ATP binding. D392A: a Walker-B motif mutant designed to disrupt ATP binding. E393Q: a Walker-B motif mutant designed to disrupt ATPase activity. ATP hydrolysis is expressed as moles of ATP hydrolysed per minute per mole of AriA hexamer. Error bars represent the average and standard deviation of three measurements (n = 3; open circles). d, A representative plaque-forming unit assay, demonstrating T7 phage plaques on the E. coli MG1655 bacterial lawn carrying either an empty vector (EV), the PARIS system (AriA-AriB, as an operon), the ATPase mutant AriAE393Q (AriAEQ-AriB), or a putative nuclease-dead mutant AriBE90A (AriA-AriBE90A). T7 phage 10-fold dilutions are spotted as indicated with a gradient. e, f, Growth curve assays depicting the effects of AriB or AriA-AriB overexpression in E. coli MG1655 bacterial cells. The presence and absence of inducers, as well as their relative concentrations, are indicated above. Curves and error bars represent average ± standard deviation from three independent replicates (n = 3), and are representative of two independent trials. g, h, i, Schematic representations illustrating expression strategies and size exclusion chromatography coupled to multi-angle light scattering (SEC-MALS) analysis of AriA, AriA-AriBE90A, and AriA-AriBE90A + AriBE90A complexes. Blue lines depict protein concentration (dRI; change in refractive index from baseline), while orange lines indicate measured molecular mass in kDa. The theoretical molecular weights for each subunit and the inferred complexes are indicated within each SEC-MALS plot.
