Zhao J, Nussinov R, Ma B. Mechanisms of recognition of amyloid-β (Aβ) monomer, oligomer, and fibril by homologous antibodies.
J Biol Chem 2017;
292:18325-18343. [PMID:
28924036 PMCID:
PMC5672054 DOI:
10.1074/jbc.m117.801514]
[Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/26/2017] [Indexed: 12/31/2022] Open
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-β (Aβ) 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 Aβ pentamer (oligomer model) and 16-mer (fibril model). It is noteworthy that solanezumab targets Aβ 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 Aβ 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 Aβ aggregates. Collectively, we provide molecular insight into the recognition mechanisms facilitating antibody design.
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