Antibodies are large, multi-chain proteins which play a critical roll in the func-tioning of vertebrate immune systems. Immune effector cells which are responsiblefor the destruction of foreign antigens do not randomly target molecules but rely onantibodies to recognize and bind antigens with very high specificity before initiatingthe process of antigen destruction. This process, known as antibody-dependent cel-lular cytotoxicity (ADCC), involves coordination of binding sites on the surfaces ofantibodies that are distant from each other implying an allosteric mechanism. Frommolecular dynamics data, an effective elastic network model (ENM) of an IgG4 mon-oclonal antibody is constructed from the inverse of a noise-decorrelated covariancematrix. A perturbation-response method is then applied which demonstrates longrange correlations exist between antibody residues. The correlations between thesedistant sites are then shown to have potential site specific cooperative binding free en-ergies which strongly suggest the presence of dynamic allosteric effects. Of particularsignificance, our results confirm the putative allosteric pathways directly connectingthe functionally important CH2 domains to the complementarity determining regions(CDRs). Our results also show that this functional allosteric pathway is highly sensi-tive to mutations. This finding launches a potential paradigm shift in how antibodiesuse molecular cooperativity as part of their function.
