Structure of GbpA.

<p><b>A.</b> Schematic representation of the functional domains of GbpA. The residue boundaries for each domain of the determined structure of GbpA are numerically labelled above the diagram. The N-terminus SP box refers to the signal peptide that signals the protein for secretion through the type-2 secretory pathway. <b>B.</b> Stereo images of the crystallised structure of GbpA_D1–3. The structure is coloured according to the secondary structure for each domain. For domain 1, the α-helices are coloured blue, β-sheets are coloured in red. For domain 2, the α-helices are coloured in brown, and the β-sheets are coloured in cyan. For domain 3, the β-sheets are coloured in yellow. All strands are coloured in grey. The residues defining domain boundaries are labelled accordingly. The disulfide bonds are coloured as two yellow coloured sticks. The first and last β-strands for each domain, and all α-helices are labelled. <b>C.</b> Topology diagram of GbpA_D1–3 drawn using TOPDRAW <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002373#ppat.1002373-Bond1" target="_blank">[52]</a>. The β-stands and the α-helices are numbered sequentially. <b>D.</b> The <i>ab initio</i> SAXS model of GbpA_fl (gray spheres) is superimposed onto the structure of GbpA_D1–3 and the modelled structure of GbpA_D4 (ribbon models) as determined by rigid body refinement using SASREF.