Figure 6. Expression of His-tagged gp4 in vivo.
Cultures of cells bearing plasmids were treated as described in the legend to Figure 2 and under Materials and Methods, except samples were taken at 3 times as indicated in the figure. HK97 protein bands are identified in the figure. (a). Cleavage of HK97 major capsid protein by 6-His protease. The HK97 major capsid protein was expressed together with the wild-type protease from plasmid pV0 , and with the His-tagged protease from plasmid pTQ30-6Hisgp4–g5. (b). Expression of the His-tagged protease by itself from plasmid pT7-6-6Hisgp4–38. The protease is rapidly cleaved to form a new band with a molecular weight a few kDa smaller; a band with an even lower molecular weight appears later. (b). Stabilization of His-gp4 by co-expression with gp5 N-terminal fragment. When the His-tagged protease is expressed from plasmid pTQ30-6Hisgp4-RV, the protease appears to stabilized by the N-terminal fragment of the major capsid protein that is co-expressed.