Plasmid #1 encodes all three ttRNAP subunits with a C-terminal CL7 tag. Bsu36I/SwaI, HindIII/SfiI, and AhdI/SpeI restriction sites flank subunits 1, 2, and 3, respectively. Additionally, Bsu36I/SpeI excises the full 10kb restriction fragment containing all three subunits.