Fig. 3.
Mapping of key residues affecting IL-13 binding onto a space-filling structural model of the BAK1.1 Fv from the viewpoint of the antigen. The model shows the VH chain on the left and the VL chain on the right, and the six CDRs composing the antigen-combining site are labeled. Hotspot positions (in which residues were found to be mutated independently in two or more variants of improved potency) derived from in vitro evolution are shown in red. CDR residues that, upon mutation to alanine, were shown to reduce their maximal binding (Rmax) to an IL-13-coated Biacore surface by >70%, are shown in dark blue. The two populations show distinct distributions over the antibody V-region surface.