Staphylococcal enterotoxin-like X (SElX) is a unique superantigen with functional features of two major families of staphylococcal virulence factors
Fig 5
The structural analysis of SElX.
(A) crystal structure of SElX8 (cyan) in complex with sLeX (green) shown from the left of the glycan binding site (left panel) and from the right of the glycan binding site (right panel). (B) The sialylated glycan-binding site of SElX8 (blue) showing the residues that hydrogen-bond (yellow dotted lines) with sLeX (green). The side chains that interact with sLeX are labelled and shown in bold. The components of sLeX are labelled as follows: N-Acetylneuraminic Acid (S); galactose (G); fucose (Fuc); and N-Acetylglucosamine (N). (C) Structural overlay of SElX8 (blue) with the SAg TSST-1 (silver) and SSL5 (sage). (D) Comparison of sialyl Lewis X (sLeX) (in green) bound in the glycan binding sites of SElX8 (blue), SSL4 (silver), SSL5 (sage), and SSL11 (orange). The side chains of residues that hydrogen-bond with sLeX are shown in bold. An overlay of these binding sites (centre) shows the conservation of residues that interact with sLeX.