Antibody-hapten interactions enhancement

The van der Waals and hydrogen bond interactions present in AZ-28 force the hapten into a fixed conformation that is cat-alyticaUy unfavorable. In contrast, the antibody combining site of the germline precursor to AZ-28 seems to have much more flexibility, allowing dynamic changes that lead to enhanced orbital overlap and increased rate acceleration. The disparity in catalysis is further supported by molecular dynamics simulation... 

The fluorescence enhancement and the shift to blue indicate that water is largely excluded from the combining site when the hapten is bound. Hydrophobic interactions contribute significantly to the formation of most antigen-antibody complexes. 

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