(A) Partial map of plasmid pET::34.1 containing the 34.1 gene, showing the direction of transcription and the locations of the T7 promoter, the His tag, and the NdeI and BamHI sites used for cloning. The amino acid sequence of His-tagged Chu is shown with the Chu sequence in bold. (B) Induction of SPP1 Chu expression. SDS-PAGE of whole-cell lysates of BL21-CodonPlus (DE3)-RP [pET::34.1] cells (RIK 238) 3 and 0 h after induction with IPTG (lanes 1 and 2, respectively) shows the appearance of the expected 38-kDa band. Expression of Chu in BL21(DE3) pLysS [pET::34.1] cells (RIK 237) was not detected. Lanes 5 and 6 show whole-cell lysates 0 and 3 h, respectively, after induction with IPTG. (C) SDS-polyacrylamide gel of pure His-tagged Chu.