Proteoglycan arrangement in tendon collagen bundles
Vidal, B.C.; Mello, M.L.
Cellular and Molecular Biology 30(3): 195-204
1984
ISSN/ISBN: 0145-5680 PMID: 6467285 Document Number: 229361
Proteoglycan arrangement was investigated with polarizing and electron microscopes in the extracellular matrix of tendons of newborn rats. Based on linear dichroism data, the long axis of the AGAG molecules is supposed to be positioned predominantly parallel to the long axis of the collagen fibrils. A helical conformation is suggested for the AGAG molecules. Ultrastructural images of Ru red (RR) fixed material demonstrated dense globules connected among themselves and attached to the cell coat through fibrillary formations. These were seen to be attached to globules disposed on the same collagen fibril or connecting globules from different collagen fibrils. The fibrillary formations are assumed to represent proteoglycans, whereas the granules are supposed to be places where proteoglycans are attached to a linking protein (possibly a glycoprotein). Based on anisotropic data and ultrastructural images of RR-fixed material, a schematic model for the spatial arrangement of the components involved is proposed.