Antigen recognition by antibody C836 through adjustment of V_L/V_H packing

C836 is a neutralizing monoclonal antibody to human interleukin IL-13 generated by mouse immunization. The crystal structure of the C836 Fab was determined at 2.5 Å resolution and compared with the IL-13-bound form determined previously. This comparison indicates an induced-fit mechanism of antigen recognition through rigid-body rotation of the V_L and V_H domains. The magnitude of this rearrangement is one of the largest observed for antibody-protein interactions.