FIG. 1.

Physical maps of the plasmids. The plasmid pGST4AC20X was obtained by inserting the 0.895-kb EcoRV-XhoI fragment of cry4A into the SmaI-XhoI site of pGEX-4T-3 (Pharmacia Biotech). This plasmid encoded GST-20, the fusion protein of GST linked to the segment spanning Pro³⁰ to Arg²³⁵ of Cry4A. The plasmid pGST4A45 was constructed by subcloning the 1.35-kb MunI-SalI fragment of pLH4-B2-Sal, which was obtained by inserting the SalI linker into the SacI site of pLH4-B2 (28), into the BamHI-SalI site of pGEX-4T-3. The plasmid pGST4A45 encoded GST-45, the fusion protein of GST linked to the segment spanning Ile²⁴⁷ to Lys⁶⁹⁵ of Cry4A. The plasmid pGST4A60 was constructed to express GST-60, the fusion protein of GST linked to the segment spanning Met¹ to Lys⁶⁹⁵ of Cry4A, by inserting the 2.03-kb cry4A fragment into BamHI-SalI site of pGEX-4T-3. The plasmid pET4A45-His was obtained by inserting the 1.35-kb MunI-SalI fragment from pLH4-B2-Sal into the EcoRI-SalI site of pET21c (Novagen) to express 45His, the 6×His-tagged segment spanning Ile²⁴⁷ to Lys⁶⁹⁵ of Cry4A.