Fig. 2. The Csy–AcrIF9 complex binds non-sequence-specific DNA.

a Csy–AcrIF9 binds target and non-target DNA as shown by EMSA. Csy (200 nM) is incubated for 15 min with increasing concentrations of AcrIF9 prior to the addition of ³²P-labeled target or non-target DNA. A proportion of the non-specifically bound DNA dissociates from Csy‧AcrIF9 during gel electrophoresis. Data are provided as a Source Data file. b Model of the Csy–AcrIF9–dsDNA complex, Csy–AcrIF9 shown as pipes and planks with Gaussian-filtered EM density of the non-uniform refinement. c, d View of the Gaussian-filtered EM density of the non-uniform refinement at the AcrIF9.1 and AcrIF9.2 sites. e Electrostatic surface of the AcrIF9 DNA binding face, shown as a transparent surface, basic residues shown as sticks.