title: Location of the binding site in subcomponent C1q for plasma fibronectin.
abstract: Previous studies on the interaction of fibronectin with C1q have yielded apparently conflicting results since both the globular head regions (produced by collagenase digestion) and the collagen-like domains (produced by limited pepsin digestion) have been reported to bind to fibronectin. In this study, the binding of 125I-labelled fibronectin to either intact C1q, or the collagenase or pepsin digestion products, immobilised on plastic microtitre plates was examined. Inhibition of the C1q-fibronectin interaction by the C1q digestion products was also examined. The results confirmed that both globular 'head' region preparations and collagen-like region preparations, can interact with fibronectin. Since the fragments used in these studies share a section of common amino acid sequence from the C1q molecule it can be concluded that the binding site, on C1q for fibronectin, is located in a region formed from the residues 81-97 of each of the three chains of the C1q molecule.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003094:Collagen / Q000378:metabolism; D003166:Complement Activating Enzymes / Q000378:metabolism*; D015922:Complement C1q; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D010446:Peptide Fragments / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D005353:Fibronectins; D010446:Peptide Fragments; D015922:Complement C1q; D003094:Collagen; D003166:Complement Activating Enzymes