an experimental model was devised to test if hcv full-length polyprotein sequence with a mutation (either h143a or c184a) would give ns2-3 cleaved polyprotein. expression of two mutants in the same experimental model should yield ns2 and ns3 as it would provide with one active site. as the data shown in the paper, ns2 and ns3 were cleaved which meant that co-expression of two mutants did yield at least one functional active site.