Conformational changes during proteolytic processing of a picornavirus capsid proteins - Brief report

We have used synthetic peptide antibodies to probe conformational changes t hat occur during the cleavage cascade which generates the capsid proteins o f a picornavirus. The initial translation product of 97 kDa, the precursor of all four structural proteins, is cleaved to form a 63 kDa fragment which , we show, has significantly different folding characteristics to both its larger parent and its products. We demonstrate that proteolytic cleavages a s distant as 520 residues from epitopes confer sufficiently large conformat ional changes as to render them unrecognisable. To our knowledge, this is t he first demonstration of this phenomenon in the picornavirus system.