A refined model for the TSG-6 link module in complex with hyaluronan: Use of defined oligosaccharides to probe structure and function

Research output: Contribution to journalArticle

  • External authors:
  • Victoria A. Higman
  • David Briggs
  • David J. Mahoney
  • Charles Blundell
  • Benedict M. Sattelle
  • Dixy E. Green
  • Paul L. DeAngelis


Tumor necrosis factor-stimulated gene-6 (TSG-6) is an inflammation- associated hyaluronan (HA)-binding protein that contributes to remodeling of HA-rich extracellular matrices during inflammatory processes and ovulation. The HA-binding domain of TSG-6 consists solely of a Link module, making it a prototypical member of the superfamily of proteins that interacts with this high molecular weight polysaccharide composed of repeating disaccharides of D-glucuronic acid and N-acetyl-D-glucosamine (GlcNAc). Previously we modeled a complex of the TSG-6 Link module in association with an HA octasaccharide based on the structure of the domain in its HA-bound conformation. Here we have generated a refined model for a HA/Link module complex using novel restraints identified from NMR spectroscopy of the protein in the presence of 10 distinct HA oligosaccharides (from 4- to 8-mers); the model was then tested using unique sugar reagents, i.e. chondroitin/HA hybrid oligomers and an octasaccharide in which a single sugar ring was 13C-labeled. The HA chain was found to make more extensive contacts with the TSG-6 surface than thought previously, such that a D-glucuronic acid ring makes stacking and ionic interactions with a histidine and lysine, respectively. Importantly, this causes the HA to bend around two faces of the Link module (resembling the way that HA binds to CD44), potentially providing a mechanism for how TSG-6 can reorganize HA during inflammation. However, the HA-binding site defined here may not play a role in TSG-6-mediated transfer of heavy chains from inter-α-inhibitor onto HA, a process known to be essential for ovulation. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Bibliographical metadata

Original languageEnglish
Pages (from-to)5619-5634
Number of pages15
JournalJournal of Biological Chemistry
Issue number9
StatePublished - 28 Feb 2014