The ability of the immune system to generate specific antibodies for virtually any antigen has been exploited in many different applications. Specifically, antibodies against small molecules (haptens) are used as catalysts, diagnostic test systems and in immunopharmacotherapy. In particular, monoclonal antibodies have been developed for the purposes of catalytic drug degradation and active immunization in the treatment of cocaine abuse. Antibodies for these applications are produced using hybridoma technology, but their qualities could be further improved through rational design if the structural determinants of binding specificity were understood. The almost unlimited diversity of possible antigens and the structural flexibility of antigen-binding sites make antibodies an outstanding model to study protein–ligand interactions in general. Thus, a better understanding of how antibodies bind small ligands and what determines binding affinity and specificity would also greatly benefit the broader field of structural studies of protein–ligand interactions and structure-based drug design. Binding sites in antibodies are constructed from the same building blocks as they are in any protein. The task of evolving a perfect binding site on the antibody surface for a specific ligand is complementary to the task of developing an inhibitor molecule that binds in the active site of an enzyme. Both rely heavily on our knowledge of molecular recognition, the mechanisms through which highly specific and tight association of proteins and ligands is achieved. Here you can see a crystal structure of a murine antibody complexed to cocaine (PDB code: 1Q72)

#molecularart #antibody #diagnostics #cocaine #murine #xray

Structure rendered with @proteinimaging, post-processed with @stylar.ai_official and depicted with @corelphotopaint