A diverse group of macromolecules Formed by covalently and noncovalently aggregating proteins andglycosaminoglycans in the extracellular matrix A bottlebrush-like molecular architecture“Bristles” noncovalently attached to a filamentous hyaluronate backbone The bristles consisting of a core protein with glycosaminoglycans Most often keratan sulfate and chondroitin sulfate The interaction between the core protein and the hyaluronate stabilizedby a link protein Smaller oligosaccharides usually attached to the core protein near its siteof attachment to hyaluronate Smaller oligosaccharides in the form of N-linked oligosaccharides Glycosidically linked to the protein via the amide N of specific Asn residues The keratan sulfate and chondroitin sulfate chains glycosidically linked tothe core protein via oligosaccharides O-linked oligosaccharides Covalently bonded to side chain O atoms of specific Ser or Thr residues