Figure 4 - full size

 

Figure 4.
FIGURE 4. Interactions in the SEI·HA·DR1, SEH·HA·DR1, and SPEC·MBP·DR2a interfaces. A, interactions between the HLA-DR1 -chain (blue) and SEI (yellow) in the SEI·HA·DR1 complex. The DR1 -chain (green) does not contact SEI. Residues of the DR1 -chain involved in interactions with SEI are green. The interface zinc ion is drawn as a red sphere. Hydrogen bonds are represented as dashed lines. Oxygen and nitrogen atoms are colored red and blue, respectively. B, interactions between the HA peptide (pink) and SEI (yellow). Peptide residues P–1 Lys and P2 Val (purple) contact the SAG. C, Zn^2+ coordination in the SEI·HA·DR1 complex. The zinc ion is tetrahedrally coordinated by SEI residues His^169, His^207, and Asp^209 (yellow) and by HLA-DR1 residue His^81 (green). D, interactions between the HLA-DR1 -chain (blue) and SEH (yellow) in the SEH·HA·DR1 complex. Residues Asp-55 and Asn^57 of the DR1 -chain (green) also contact SEH. E, interactions between the HA peptide (pink) and SEH (yellow). Peptide residues P–1 Lys and P3 Lys (purple) contact the SAG. F, Zn^2+ coordination in the SEH·HA·DR1 complex. The zinc ion is coordinated by SEH residues His^206 and Asp^208 (yellow) and by DR1 residue His^81 (green). G, interactions between the HLA-DR2a -chain (blue) and SPEC (yellow) in the SPEC·MBP·DR2a complex. The DR2a -chain (green) does not contact SPEC. H, interactions between the MBP peptide (pink) and SPEC (yellow). Peptide residues P–3 Val, P–2 His, P–1 Phe, P2 Lys, and P3 Asn (purple) contact the SAG. I, Zn^2+ coordination in the SPEC·MBP·DR2a complex. The zinc ion is coordinated tetrahedrally by SPEC residues His^167, His^201, and Asp^203 (yellow) and by HLA-DR2a residue His^81 (green).

The above figure is reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 25356-25364) copyright 2006.