Summary
Following fragmentation of the collagen molecule, we have examined the ability of
the isolated fragments to bind vWf. In view of the importance of collagen tertiary
and quaternary structure for binding, fragments were first renatured to restore triple-helical
conformation and then polymerized. Results indicate the presence of specific vWf-binding
sites in both the αl(I)-and α2(I)-chains of type I collagen. Cleavage of the αl(I)-chain
with cyanogen bromide suggests the presence of at least four (conceivably several
more) binding sites implying a wide distribution of sites along the length of the
collagen type I molecule. Collagen type III appears to possess a similar wide distribution
of sites. Chemical modification of specific amino acid residues indicates that interaction
involves arginyl residues in collagen and carboxyl groups in vWf. Although interaction
between fibronec-tin and collagen fibres also involves collagen arginyl residues and
carboxyl groups in fibronectin (authors’ unpublished results), fibronectin does not
compete with vWf in the binding to collagen fibres.
Keywords
Collagen - von Willebrand factor - Fibronectin