FIG. 5.

In vitro trans cleavage efficiency of PLP-1 increases with increase substrate length. Plasmid pSPNK H1272P was digested with the enzymes indicated at the top followed by transcription and translation in the coupled system in the presence of [³⁵S]methionine. The radiolabeled viral substrates were incubated with unlabeled mutant PLP-1 H1272P (A) or wild-type PLP-1 (B), also synthesized in the coupled transcription-translation using pET-PLP-1 H1272P or pET-PLP-1, respectively, as the templates. Cleavage products were immunoprecipitated with UP102 and then analyzed by SDS–10% polyacrylamide gel electrophoresis; p28 is indicated by the arrow. The molecular masses of marker proteins are indicated between the panels.