Figure 1.

Schematic structure of bovine aggrecan. The aggrecan core protein comprises three globular domains (G1, G2 and G3) with an extended interglobular domain (IgD) between G1 and G2, and a larger extended region between G2 and G3. Keratan sulfate is substituted on the core protein primarily in a KS-rich region near G2. KS chains are also found on the G1 domain and IgD. Chondroitin sulfate chains are substituted throughout the extended region between the KS-rich region and G3. N-glycans are found on G1 and the IgD, and near G3.