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Intra- and intermolecular interactions of human galectin-3: assessment by full-assignment-based NMR.
- Source :
- Glycobiology; Aug2016, Vol. 26 Issue 8, p888-903, 16p
- Publication Year :
- 2016
-
Abstract
- Galectin-3 is an adhesion/growth-regulatory protein with a modular design comprising an N-terminal tail (NT, residues 1-111) and the conserved carbohydrate recognition domain (CRD, residues 112-250). The chimera-type galectin interacts with both glycan and peptide motifs. Complete 13C/15N-assignment of the human protein makes NMR-based analysis of its structure beyond the CRD possible. Using two synthetic NT polypeptides covering residues 1-50 and 51-107, evidence for transient secondary structure was found with helical conformation from residues 5 to 15 as well as prolinemediated, multi-turn structure from residues 18 to 32 and around PGAYP repeats. Intramolecular interactions occur between the CRD F-face (the 5-stranded β-sheet behind the canonical carbohydrate- binding 6-stranded β-sheet of the S-face) and NT in full-length galectin-3, with the sequence P23GAW26. .P37GASYPGAY45 defining the primary binding epitope within theNT.Work with designed peptides indicates that the PGAXmotif is crucial for self-interactions between NT/CRD. Phosphorylation at position Ser6 (and Ser12) (a physiological modification) and the influence of ligand binding have minimal effect on this interaction. Finally, galectin-3 molecules can interact weakly with each other via the F-faces of their CRDs, an interaction that appears to be assisted by their NTs. Overall, our results add insight to defining binding sites on galectin-3 beyond the canonical contact area for β-galactosides. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09596658
- Volume :
- 26
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Glycobiology
- Publication Type :
- Academic Journal
- Accession number :
- 118088598
- Full Text :
- https://doi.org/10.1093/glycob/cww021