PXD072578-1

PXD072578 is an original dataset announced via ProteomeXchange.

Title	O-glycosylation affects proteolysis of the native tear peptidome
Description	The endogenous tear peptidome plays essential roles in maintaining ocular homeostasis by stimulating immune response and participating in antimicrobial activity. The biological function of these native peptides is governed by their biochemical properties including peptide length, charge, and hydrophobicity. Accordingly, the production of native peptides within the tear film is tightly regulated through a complex interplay between circulating proteases and the proteolytic susceptibility of the protein substrate. Though glycosylation has been shown to regulate the proteolysis of specific proteins in vitro, the extent to which endogenous cleavage motifs are mediated by proximal O-glycans remains unexplored in a more complex sample. Furthermore, the existence and identity of native tear peptides bearing O-glycans has yet to be elucidated, largely due to the high analytical complexity of tear fluid and the difficulty in characterizing O-glycosylated peptides. To address this gap, we leveraged advances in mass spectrometry (MS) to provide the first observation of circulating tear O-glycopeptides, detailing their biochemical properties and overall glycan compositions. Beyond systematic profiling of the O-glycopeptidome, we employed site-specific glycoproteomic analysis followed by molecular dynamics to investigate the interplay between O-glycan proximity and proteolysis. Here, we observed that O-glycans preferentially occupy glycosites distal from the N-/C-terminus, thereby influencing distinct cleavage motifs and peptide backbones. Finally, we showed in silico that O-glycosylation can mediate the solvent accessibility of proximal cleavage residues, thus providing a structural basis for these observations. Taken together, this study defines the proteolytic landscape at the ocular surface and highlights a potential role for tear fluid O-glycans
HostingRepository	PRIDE
AnnounceDate	2026-07-08
AnnouncementXML	Submission_2026-07-08_05:50:48.074.xml
DigitalObjectIdentifier
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Unsupported dataset by repository
PrimarySubmitter	Vincent Chang
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: NEWT:9606;
ModificationList	2-pyrrolidone-5-carboxylic acid (Gln); complex glycosylation; deamidated residue; iodoacetamide derivatized residue
Instrument	Orbitrap Eclipse

Revision	Datetime	Status	ChangeLog Entry
0	2026-01-02 07:35:28	ID requested
⏵ 1	2026-07-08 05:50:48	announced

10.1021/JACSAU.6C00834;

submitter keyword: cleavage, mass spectrometry, glycoproteomics,peptidome, glycopeptidome, proteolysis, tear fluid

Stacy Malaker
contact affiliation	Department of Chemistry
contact email	stacy.malaker@yale.edu
lab head
Vincent Chang
contact affiliation	Yale University
contact email	vincent.chang@yale.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD072578
     1. Label: PRIDE project
     2. Name: O-glycosylation affects proteolysis of the native tear peptidome