Linked Life Data

21264968

Source:http://linkedlifedata.com/resource/pubmed/id/21264968

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
8
pubmed:dateCreated
2011-2-14
pubmed:abstractText
Despite the growing importance of mucin core O-glycosylation in many biological processes including the protection of epithelial cell surfaces, the immune response, cell adhesion, inflammation, and tumorigenesis/metastasis, the regulation mechanism and conformational significance of the multiple introduction of ?-GalNAc residues by UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferases (ppGalNAcTs) remains unclear. Here we report an efficient approach by combining MS and NMR spectroscopy that allows for the identification of O-glycosylation site(s) and the effect of O-glycosylation on the peptide backbone structures during enzymatic mucin domain assembly by using an isoform UDP-GalNAc:polypeptide N-acetylgalactosaminyltransferase-T2 (ppGalNAcT2) in vitro. An electron-capture dissociation device in a linear radio-frequency quadrupole ion trap (RFQ-ECD) combined with a time-of-flight (TOF) mass spectrometer was employed for the identification of Thr/Ser residues occupied by ?-GalNAc branching among multiple and potential O-glycosylation sites in the tandem repeats of human mucin glycoproteins MUC4 (Thr-Ser-Ser-Ala-Ser-Thr-Gly-His-Ala-Thr-Pro-Leu-Pro-Val-Thr-Asp) and MUC5AC (Pro-Thr-Thr-Val-Gly-Ser-Thr-Thr-Val-Gly). In the present study, O-glycosylation was initiated specifically at Thr10 in naked MUC4 peptide and additional introduction of ?-GalNAc proceeded preferentially but randomly at three other Thr residues to afford densely glycosylated MUC4 containing six ?-GalNAc residues at Thr1, Ser2, Ser5, Thr6, Thr10, and Thr15. On the contrary, O-glycosylation of naked MUC5AC peptide occurred predominantly at consecutive Thr residues and led to MUC5AC with four ?-GalNAc residues at Thr2, Thr3, Thr7, and Thr8. The solution structures determined by NMR spectroscopic studies elicited that the preferential introduction of ?-GalNAc at Thr10 of MUC4 stabilizes specifically a ?-like extended backbone structure at this area, whereas other synthetic models with a single ?-GalNAc residue at Thr1, Thr6, or Thr15 did not exhibit any converged three-dimensional structure at the proximal peptide moiety. Such conformational impact on the underlying peptides was proved to be remarkable in the glycosylation at the consecutive Thr residues of MUC5AC.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1521-3765
pubmed:author
pubmed:copyrightInfo
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
pubmed:issnType
Electronic
pubmed:day
18
pubmed:volume
17
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2393-404
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
An efficient approach for the characterization of mucin-type glycopeptides: the effect of O-glycosylation on the conformation of synthetic mucin peptides.
pubmed:affiliation
Graduate School of Life Science and Frontier Research, Center for Post-Genome Science and Technology, Hokkaido University, Sapporo 001-0021, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't