OVERLAPPING SITES ON THE LINK MODULE OF HUMAN TSG-6 MEDIATE BINDING TO HYALURONAN AND CHONDROITIN-4-SULFATE

Link modules are hyaluronan-binding domains that are involved in the f ormation and stability of extracellular matrix and cell migration. We have examined the glycosaminoglycan specificity of the Link module fro m the arthritis-associated protein, human TSG-6, by microtitre plate-b ased assays employing biotinylated-hyaluronan or mono-biotinylated Lin k module. This domain was found to interact specifically,vith chondroi tin-4-sulphate (C4S), with similar affinity to hyaluronan, but not wit h chondroitin-6-sulphate or heparin. Competition experiments indicate that C4S and hyaluronan have overlapping binding surfaces on the TSG-6 Link module. Disease-associated changes in C4S expression may influen ce the localisation and biological role of TSG-6. (C) 1997 Federation of European Biochemical Societies.