Figure 1

Structure of the D5-5-Helix interaction and similarities to CR6261. (a) Crystal structure of the D5-5-Helix complex reported by Luftig et al. (ref. 6, PDB ID 2CMR). The D5 light chain is colored in red, the D5 heavy chain in blue, and 5-Helix in yellow; side chains of residues involved in the interface are shown in stick. The critical HCDR2 is boxed. (b) Similarity of interactions involving HCDR2 in D5 and CR6261 (ref. 11, PDB ID 3GBN). In both antibody-antigen complexes, F54 of HCDR2 (a germline-encoded residue) inserts into a hydrophobic cleft on the antigen (here, shown in gray). The amino acid sequence of HCDR1 and HCDR2 regions from V_H1-69, D5, and CR6261 are also shown. (c) Cross-reactivity analysis of phage clones displaying the bivalent scFv (biv-scFv) of D5 and CR6261. Phage titers were ~ 10¹² infectious units/mL for both clones.