NMR insight into the multiple glycosaminoglycan binding modes of the Link module from human TSG-6.
Related Articles NMR insight into the multiple glycosaminoglycan binding modes of the Link module from human TSG-6.
Biochemistry. 2015 Dec 18;
Authors: Park Y, Jowitt TA, Day AJ, Prestegard JH
Abstract
Tumor necrosis factor-stimulated gene-6 (TSG-6) is a hyaluronan (HA) binding protein that is essential for stabilizing and remodelling the extracellular matrix (ECM) during ovulation and inflammatory disease processes such as arthritis. The Link module, one of the domains of TSG-6, is responsible for binding hyaluronan and other glycosaminoglycans (GAGs) found in the ECM. In this study, we used a well-defined chondroitin sulfate (CS) hexasaccharide (?C444S) to determine the structure of the Link module, in solution, in its chondroitin sulfate bound state. A variety of NMR techniques were employed, including chemical shift perturbation, residual dipolar couplings (RDCs), NOEs, spin relaxation measurements, and paramagnetic relaxation enhancements (PREs) from a spin-labeled analog of ?C444S. The binding site for ?C444S on the Link module overlapped with that of HA. Surprisingly, ?C444S binding induced dimerization of the Link module (as confirmed by analytical ultracentrifugation), and a second weak binding site that partially overlapped with a previously identified heparin site was detected. A dimer model was generated using chemical shift perturbations and RDCs as restraints in the docking program HADDOCK. We postulate that the molecular cross-linking enhanced by the multiple binding modes of the Link module may be critical for remodeling the ECM during inflammation/ovulation and may contribute to other functions of TSG-6.
PMID: 26685054 [PubMed - as supplied by publisher]
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