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Pulse-chase Analysis of N-linked Sugar Chains from Glycoproteins in Mammalian Cells
Published on: April 27, 2010
Repetitive Ser-Gly sequences enhance heparan sulfate assembly in proteoglycans
1Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham 35294, USA.
The Journal of Biological Chemistry
|November 10, 1995
Summary
Heparan sulfate synthesis is controlled by specific amino acid sequences in proteoglycans. Repeat units like Ser-Gly and acidic residues near glycosylation sites dictate heparan sulfate assembly.
Area of Science:
- Biochemistry
- Molecular Biology
- Glycobiology
Background:
- Heparan sulfate (HS) synthesis on betaglycan occurs at Ser-Gly dipeptides near acidic residues and tryptophan.
- Most HS proteoglycans feature repetitive (Ser-Gly)n segments (n=2) and adjacent acidic residues.
Purpose of the Study:
- To investigate the role of specific amino acid sequences in controlling HS synthesis.
- To map glycosylation sites on Chinese hamster ovary (CHO) cell syndecan-1.
Main Methods:
- Construction of chimeric proteoglycans using CHO syndecan-1 cDNA fused to Protein A.
- Analysis of glycosaminoglycan assembly at different mapped sites.
Main Results:
- Two sites near the transmembrane domain synthesized only chondroitin sulfate.
- Three N-terminal sites synthesized both HS and chondroitin sulfate.
- The repeat unit -S45GS47G- showed the strongest HS synthesis, with coupling between adjacent SG dipeptides enhancing HS proportion.
Conclusions:
- Sequence motifs, including (Ser-Gly)n repeats and adjacent acidic residues, are crucial for HS assembly at glycosylation sites.
- These findings provide predictive rules for HS synthesis on proteoglycan core proteins.
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