y Degradation of Alzheimer's Amyloid-beta by a Catalytically Inactive Insulin-Degrading Enzyme

• It is known that insulin-degrading-enzyme (IDE) plays a crucial role in the clearance of Alzheimer's amyloid-beta (A beta). The cysteine-free IDE mutant (cf-E111Q-IDE) is catalytically inactive against insulin, but its effect on A beta degradation is unknown that would help in the allosteric modulation of the enzyme activity. Herein, the degradation of A beta(1-40) by cf-E111Q-IDE via a non-chaperone mechanism is demonstrated by NMR and LC-MS, and the aggregation of fragmented peptides is characterized using fluorescence and electron microscopy. cf-E111Q-IDE presented a reduced effect on the aggregation kinetics of A beta(1-40) when compared with the wild-type IDE. Whereas LC-MS and diffusion ordered NMR spectroscopy revealed the generation of A beta fragments by both wild-type and cf-E111Q-IDE. The aggregation propensities and the difference in the morphological phenotype of the full-length A beta(1-40) and its fragments are explained using multi-microseconds molecular dynamics simulations. Notably, our results reveal that zinc binding to A beta(1-40) inactivates cf-E111Q-IDE's catalytic function, whereas zinc removal restores its function as evidenced from high-speed AFM, electron microscopy, chromatography, and NMR results. These findings emphasize the catalytic role of cf-E111Q-IDE on A beta degradation and urge the development of zinc chelators as an alternative therapeutic strategy that switches on/off IDE's function. (C) 2021 Elsevier Ltd. All rights reserved.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

Nyckelord

Amyloid-beta

Insulin degrading enzyme

Amyloid degradation

A beta(1-40)

Alzheimer's disease

Publikations- och innehållstyp

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