(A) AFM images of the 755 bp csgD regulatory region (csgD755). (B) At 120 nM SsrB, distinct areas of SsrB binding were visualized as sharp bends (yellow arrows). (C) At 300 nM SsrB, areas of condensation (pink arrows) were observed. (D) Binding of SsrB bends the DNA by an average angle of 82º (for the naked DNA angle, refer to Figure 5—figure supplement 2 and for analysis refer to Supplementary method), Scale bar = 200 nm as in (A). (E) and (F) The SsrB mutant, K179A SsrB, which is defective in DNA binding, was unable to bind csgD755 both at 30 nM or 300 nM; Scale bar = 200 nm.