The pET-42 series is designed for cloning and high-level expression of peptide sequencesfused with the 220 aa GST?Tag? protein. Unique sites are shown on the circle map. Note that thesequence is numbered by the pBR322 convention, so the T7 expression region is reversed on thecircle map. The cloning/expression region of the coding strand transcribed by T7 RNA polymeraseis shown below. The f1 origin is oriented so that infection with helper phage will produce virionscontaining single stranded DNA that corresponds to the coding strand. Therefore, single strandedsequencing should be performed using the T7 terminator primer (cat. no. 69337-3). Vector encodedsequence can be completely removed when cloning into the PshAI site (as shown below) and thencleaving the GST fusion protein with Factor Xa.