General organization of the BvgS periplasmic domain.

<p>A. Schematic representation of the homodimeric BvgS periplasmic portion. The protomers A and B are shown in shades of green and blue, respectively. One protomer consists of two VFT domains and a C-terminal H19 α helix. B. Ribbon representation of the X-ray structure of the BvgS periplasmic domain, the same color code as in (A) is used to show the different VFTs. The two-fold symmetry axis is indicated. C. Surface representation of the periplasmic domain of BvgS. On the left, the view angle is similar to (B), while on the right, a 90° clockwise rotation along the x-axis was applied. N and C denote the N and C termini of the two protomers.