Figure 1.
Schematic representation of the complex between SpA domain D and Fab 2A2 from a human IgM. (A) Side view showing SpA domain D (red) bound to the framework region of the Fab heavy chain (cyan). The VL domain, which is not involved in this interaction, is shown in dark blue. The CDR loops as defined by Chothia and Lesk (33) are highlighted in magenta. (B) Ribbon representation of the VH region of Fab showing the positions of the residues that interact with domain D. (C) Schematic diagram detailing the residues of SpA domain D and Fab 2A2 involved in the interaction. Kabat numbering is used for the VH residues (blue); domain D is numbered (in brown) with the convention used for SpA domains (34). Contact residues are identified if 20 Å2 or more of their surface are buried in the interface and if they make at least one van der Waals contact. All figures were generated by using molmol (35).