Small-angle neutron scattering study on a proteoglycan in solution

To characterize the solution structure of the proteoglycan that is purified from shark-fin cartilage, we have been studied by small-angle neutron scattering method. The radius of gyration in 100% D2O was found to be 25.3 nm by extrapolating the sample concentration to zero. The contrast matching point was estimated to be 47.9% D2O. The Stuhrmann plots indicated that a protein is the core of the proteoglycan molecule with symmetrical distribution of neutron scattering density. The result of a shape analysis suggested that the proteoglycan molecule in solution could be described to a first approximation by a simple elongated ellipsoid. These results are consistent with the observation that proteoglycans are composed of many glycosaminoglycan chains covalently linked to the protein core. (author)