Figure 3.

(a) Sequence alignment of sialic acid-binding proteins from four different pathogenic bacteria using ClustalW2 (EMBL–EBI) and ESPript. The hinge regions are marked and labelled. Hinge 1 in shown in red and hinge 2 in blue. (b) Structural view of the conserved hinge regions of Fn-SiaP, looking down from the Neu5Ac. Hinge 1 and hinge 2 are coloured red and blue, respectively. Arg129 and His211 are also marked with the corresponding hinge colours. (c) Close-up view of conserved residues from the hinge region of Pm-SiaP in the presence of Neu5Ac. The dotted lines show residues interacting by hydrogen/ionic bonds and the distances are labelled in Å.