CHARACTERIZATION OF A LARGE CHONDROITIN SULFATE PROTEOGLYCAN PRESENT IN BOVINE COLLATERAL LIGAMENT

Bovine collateral ligament synthesized a S-35-labeled large proteoglyc an species which eluted with a K-av of similar to 0.27 on Sepharose CL -2B and contained only chondroitin sulfate chains with a molecular mas s of similar to 32 kDa. Fluorography of the S-35-labeled core proteins derived from the large ligament proteoglycan revealed a broad range o f molecular masses above similar to 200 kDa, which was of comparable s ize to the four major endogenous core protein bands derived from this proteoglycan detected with 5/6/3-B-3, an antibody directed against ter minal unsaturated chondroitin-6-sulfate disaccharides. The core protei ns derived from the large ligament proteoglycan exhibited immunoreacti vity to 12/21/1-C-6, an antibody specific for a peptide epitope common to both the G1 and G2 domains of aggrecan. Four major core protein ba nds with molecular masses greater than similar to 200 kDa derived from the large ligament proteoglycan, were detected using the antibodies r aised against versican from bovine aorta or human fibroblasts. Compare d with aggrecan, the S-35-labeled large ligament proteoglycan was dist ributed over a broader range of buoyant densities in an associative ca esium chloride density gradient. This polydispersity may he indicative of differences in the degree of glycosylation as well as heterogeneit y in the size of the large ligament proteoglycan core proteins. The S- 35-labeled large ligament proteoglycan also demonstrated the ability t o form complexes with an aggrecan aggregate preparation, the majority of which could not be dissociated by the presence of HA(10-50). These findings indicate that the large chondrotin sulfate proteoglycan synth esized by bovine collateral ligament may be a versican-like proteoglyc an which exhibited the potential to form link protein-stabilized compl exes. (C) 1996 Academic Press, Inc.