Fig. 3: Structure and activities of ShosA.
From: A toxin-antitoxin system provides phage defense via DNA damage and repair
a Crystal structure of ShosA C-terminal truncation. The SAM and DprA domains are colored in light orange and orange. b Superimposition of ShosA and Streptococcus pneumoniae DprA. c Structure of ShosA SAM domain. d Structure of ShosA Rossmann-fold domain. e The electrostatic surface potential of ShosA. Blue and red (±5 kT/e) indicate the positively and negatively charged areas of the protein, respectively. f ShosA binds ssDNA in vitro. Electrophoretic mobility shift assay is performed using 5’ Cy3-labeled 54-nt ssDNA. Different concentrations of ShosA proteins (from 0 to 0.8 μM) were incubated with 0.1 μM DNA. Percent of the free DNA is calculated based on the gray scanning analysis. This experiment is repeated three times independently with similar results. g Representative plating assay showing the ShosT toxicity with indicated ShosA mutants. The arabinose concentrations used for inducing are indicated.
