FIGURE 3.

Crystal structure of DPP-IV in complex with the Fab of Ab1. A, overall view of the complex structure. DPP-IV and Fab are shown in ribbon representation with DPP-IV colored in magenta helices, cyan β-strands, and wheat loops and Fab colored in yellow for light chain (LC) and orange for heavy chain (HC). The blades 1 and 2 in the β-propeller domain of DPP-IV are colored in blue and green, respectively. B, the propeller and side openings in DPP-IV. The protein is shown in both ribbon and molecular surface representations. C and D, Ab1 Fab recognition of DPP-IV. The CDR loops of Ab1 are colored in red and labeled as CDR-L1, CDR-L2, and CDR-L3 and CDR-H1, CDR-H2, and CDR-H3 for light chain and heavy chain, respectively. The Fab is shown in both ribbon and molecular surface representations in D. The key epitope residues of DPP-IV binding Fab are highlighted in stick representation. E, A1 Fab recognition of DPP-IV in molecular surface representation.