Epitope Mapping by NMR of a Novel Anti-A? Antibody (STAB-MAb).

ABSTRACT: Alzheimer´s Disease (AD) is one of the most common neurodegenerative disorders worldwide. Excess of ?-amyloid (A?), a peptide with a high propensity to misfold and self-aggregate, is believed to be the major contributor to the observed neuronal degeneration and cognitive decline in AD. Here, we characterize the epitope of a novel anti-A? monoclonal antibody, the STAB-MAb, which has previously demonstrated picomolar affinities for both monomers (KD?=?80 pM) and fibrils (KD?=?130 pM) of A?(1-42) and has shown therapeutic efficacy in preclinical mouse models of AD. Our findings reveal a widespread epitope that embraces several key A? residues that have been previously described as important in the A? fibrillation process. Of note, STAB-MAb exhibits a stronger affinity for the N-terminus of A? and stabilizes an ?-helix conformation in the central to N-terminal region of the peptide, in addition to disrupting a characteristic salt-bridge of a hairpin structure present in fibrils. The NMR derived epitope supports the observed results from ThT-monitored fluorescence and electron microscopy experiments, in which STAB-MAb was shown to inhibit the formation of aggregates and promote disruption of pre-formed fibrils. In combination with the published in vitro and in vivo assays, our study highlights STAB-MAb as a rare and versatile antibody with analytical, diagnostic and therapeutic efficacy.

SUBMITTER: Posado-Fernandez A 

PROVIDER: S-EPMC6706428 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature