Crystal structure of human germline antibody 3-23/B3.

The human antibody repertoire is dominated by a few combinations of germline sequences, with the genes 3-23 for the heavy chain and B3 for the light chain being among the most frequently used. Despite this fact, there was no experimental structure of the antibody composed of 3-23 and B3. The crystal structure of the Fab fragment of the synthetic antibody composed of the 3-23 and B3 germline sequences was determined to provide a template for antibody modeling. The antigen-binding loops were found in the canonical conformations. Comparison to the other structures where either 3-23 or B3 is paired with a different chain reveals a significant deviation in the orientation of the variable domains.