Fig 6. Binding kinetics of WT-A33 and mutants to antibodies A2C7, A20G2, and A27D7.
Apparent equilibrium binding constants (KD) calculated from the binding curves shown in S3 Fig. Note that KD values can include avidity effects, since both antibodies and A33 are dimeric proteins. Grey shading qualitatively illustrates the extent of binding impairment by the indicated A33 mutation (from white, no impairment to black, full binding abrogation). Lys123Ala (K123A) was required for successful crystallization and is considered as wild-type A33 (WT) since it is located outside any MAb epitope [40].