1
|
Singh Y, Regmi D, Ormaza D, Ayyalasomayajula R, Vela N, Mundim G, Du D, Minond D, Cudic M. Mucin-Type O-Glycosylation Proximal to β-Secretase Cleavage Site Affects APP Processing and Aggregation Fate. Front Chem 2022; 10:859822. [PMID: 35464218 PMCID: PMC9023740 DOI: 10.3389/fchem.2022.859822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/07/2022] [Indexed: 12/04/2022] Open
Abstract
The amyloid-β precursor protein (APP) undergoes proteolysis by β- and γ-secretases to form amyloid-β peptides (Aβ), which is a hallmark of Alzheimer’s disease (AD). Recent findings suggest a possible role of O-glycosylation on APP’s proteolytic processing and subsequent fate for AD-related pathology. We have previously reported that Tyr681-O-glycosylation and the Swedish mutation accelerate cleavage of APP model glycopeptides by β-secretase (amyloidogenic pathway) more than α-secretase (non-amyloidogenic pathway). Therefore, to further our studies, we have synthesized additional native and Swedish-mutated (glyco)peptides with O-GalNAc moiety on Thr663 and/or Ser667 to explore the role of glycosylation on conformation, secretase activity, and aggregation kinetics of Aβ40. Our results show that conformation is strongly dependent on external conditions such as buffer ions and solvent polarity as well as internal modifications of (glyco)peptides such as length, O-glycosylation, and Swedish mutation. Furthermore, the level of β-secretase activity significantly increases for the glycopeptides containing the Swedish mutation compared to their nonglycosylated and native counterparts. Lastly, the glycopeptides impact the kinetics of Aβ40 aggregation by significantly increasing the lag phase and delaying aggregation onset, however, this effect is less pronounced for its Swedish-mutated counterparts. In conclusion, our results confirm that the Swedish mutation and/or O-glycosylation can render APP model glycopeptides more susceptible to cleavage by β-secretase. In addition, this study sheds new light on the possible role of glycosylation and/or glycan density on the rate of Aβ40 aggregation.
Collapse
Affiliation(s)
- YashoNandini Singh
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deepika Regmi
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - David Ormaza
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Ramya Ayyalasomayajula
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Nancy Vela
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Gustavo Mundim
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Deguo Du
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
| | - Dmitriy Minond
- College of Pharmacy and Rumbaugh-Goodwin Institute for Cancer Research, Nova Southeastern University, Fort Lauderdale, FL, United States
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E. Schmidt College of Science, Florida Atlantic University, Boca Raton, FL, United States
- *Correspondence: Maré Cudic,
| |
Collapse
|
2
|
Creese AJ, Grant MM, Chapple ILC, Cooper HJ. On-line liquid chromatography neutral loss-triggered electron transfer dissociationmass spectrometry for the targeted analysis of citrullinated peptides. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2011; 3:259-266. [PMID: 32938022 DOI: 10.1039/c0ay00414f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Citrullination is a post-translational modification of proteins which deiminates arginine, increasing the mass by 0.98 Da. Protein citrullination is a known biomarker for multiple sclerosis and a potential biomarker for rheumatoid arthritis. Collision-induced dissociation (CID) tandem mass spectrometry of citrullinated peptides produces a dominant neutral loss of isocyanic acid (HNCO, -43 Da) from the deiminated arginine amino acid side-chain. Here we show that the loss of isocyanic acid in CID can be used as a trigger for targeted analysis by supplemental activation electron transfer dissociation (saETD). Unlike CID, post-translational modifications (PTMs) are retained on peptide backbone fragments produced by saETD, improving the confidence in assignment of both peptide sequence and PTM site. The method is demonstrated for four synthetic peptides spiked into complex trypsin-digested saliva samples and a commercial six protein tryptic mixture. In contrast to CID alone, the neutral-loss triggered ETD approach results in high confidence identification of three of the four peptides, including an unexpected disulfide-bound dimer, and zero false positives.
Collapse
Affiliation(s)
- Andrew J Creese
- School of Dentistry, Periodontal Research Group, University of Birmingham, St Chads Queensway, Birmingham, B4 6NN, UK
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
| | - Melissa M Grant
- School of Dentistry, Periodontal Research Group, University of Birmingham, St Chads Queensway, Birmingham, B4 6NN, UK
| | - Iain L C Chapple
- School of Dentistry, Periodontal Research Group, University of Birmingham, St Chads Queensway, Birmingham, B4 6NN, UK
| | - Helen J Cooper
- School of Biosciences, University of Birmingham, Birmingham, B15 2TT, UK.
| |
Collapse
|