EVIDENCE THAT CONFORMATIONAL-CHANGES UPON THE TRANSITION OF THE NATIVE TO THE MODIFIED FORM OF VITRONECTIN ARE NOT LIMITED TO THE HEPARIN-BINDING DOMAIN

Vitronectin (Vn) exists in vivo in at least two different conformation al states, the native and the modified form, and these forms have diff erent ligand binding properties, To characterize the molecular events associated with this conformational flexibility, modified Vn was analy zed by competitive ELISA using a panel of conformationally sensitive a ntibodies with known epitopes, These studies provided evidence for maj or molecular rearrangements upon the transition from the native to the modified form that are not limited to the C-terminal heparin binding domain, but also occur in the N-terminal part of the molecule.