Figure 5.

SAXS analyses show the RsgI9 ectodomain forms an extended structure. (A) Dimensionless Kratky plots of both the RsgI9^S1C-CTD bi-domain unit (red) and intact ectodomain, RsgI9^ecto (black). The two dashed lines indicate the theoretical peak position for a typical globular protein. The bi-domain unit behaves as a compact globular protein, while the intact ectodomain forms an extended rod-like structure. (B) Distance distribution function P(r) for both RsgI9^S1C-CTD (red, D_max 82 Å) and RsgI9^ecto (black, D_max 160 Å). (C) SAXS derived electron density reconstruction of the ectodomain obtained using the program DENSS⁴⁹. The volume of electron density is colored with a gradient from blue to red to indicate regions of highest density (left). Coordinates of the crystal structure of RsgI9^S1C-CTD fitted into the electron density (right). A low-resolution model of the CRE domain that was obtained using the program DENSS and RsgI9^CRE SAXS data is also fitted into the density.