Singh Y, Ormaza D, Massetti A, Minond D, Cudic M. Tyrosine
O-GalNAc Alters the Conformation and Proteolytic Susceptibility of APP Model Glycopeptides.
ACS Chem Neurosci 2021;
12:2974-2980. [PMID:
34324289 PMCID:
PMC8378340 DOI:
10.1021/acschemneuro.1c00387]
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Abstract
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The amyloid-β precursor protein (APP) undergoes proteolytic cleavage by α-,
β-, and γ-secretases, to determine its fate in Alzheimer’s disease
(AD) pathogenesis. Recent findings suggest a possible role of
O-glycosylation in APP’s proteolytic processing. Therefore, we
synthesized native and Swedish-double-mutated APP (glyco)peptides with
Tyr681-O-GalNAc. We studied conformational changes and
proteolytic processing using circular dichroism (CD) spectroscopy and enzyme cleavage
assay, respectively. CD analysis was carried out in four solvent systems to evaluate
peptide environment and O-glycosylation induced conformational changes.
The Swedish mutation and Tyr681-O-GalNAc were the key
factors driving conformational changes. Furthermore, the level of α- and
β-secretase activity was increased by the presence of mutation and this effect was
more pronounced for its glycosylated analogues. Our results suggest that
O-glycosylation of Tyr681 can induce a conformational
change in APP and affect its proteolytic processing fate toward the amyloidogenic
pathway.
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