Mechanisms of recognition of amyloid-? (A?) monomer, oligomer, and fibril by homologous antibodies.
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ABSTRACT: Alzheimer's disease is one of the most devastating neurodegenerative diseases without effective therapies. Immunotherapy is a promising approach, but amyloid antibody structural information is limited. Here we simulate the recognition of monomeric, oligomeric, and fibril amyloid-? (A?) by three homologous antibodies (solanezumab, crenezumab, and their chimera, CreneFab). Solanezumab only binds the monomer, whereas crenezumab and CreneFab can recognize different oligomerization states; however, the structural basis for this observation is not understood. We successfully identified stable complexes of crenezumab with A? pentamer (oligomer model) and 16-mer (fibril model). It is noteworthy that solanezumab targets A? residues 16-26 preferentially in the monomeric state; conversely, crenezumab consistently targets residues 13-16 in different oligomeric states. Unlike the buried monomeric peptide in solanezumab's complementarity-determining region, crenezumab binds the oligomer's lateral and edge residues. Surprisingly, crenezumab's complementarity-determining region loops can effectively bind the A? fibril lateral surface around the same 13-16 region. The constant domain influences antigen recognition through entropy redistribution. Different constant domain residues in solanezumab/crenezumab/chimera influence the binding of A? aggregates. Collectively, we provide molecular insight into the recognition mechanisms facilitating antibody design.
SUBMITTER: Zhao J
PROVIDER: S-EPMC5672054 | biostudies-literature | 2017 Nov
REPOSITORIES: biostudies-literature
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