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. Author manuscript; available in PMC: 2008 Nov 12.
Published in final edited form as: Curr Protoc Protein Sci. 2008 May;CHAPTER:Unit–5.21. doi: 10.1002/0471140864.ps0521s52

Figure 2.

Figure 2

Creation of a polycistronic expression vector. The pST50Trc1–4 plasmids provide the translation cassettes for the 4 possible positions in the pST44 polycistronic expression vector. Specific pairs of restriction enzymes are used to subclone the translation cassettes from the pST50Trc1– 4 plasmids into pST44 (XbaI-BglII for cassette 1, EcoRI-HindIII for cassette 2, SacI-KpnI for cassette 3, BspEI-MluI for cassette 4). The XbaI-BglII translation cassette from pST50Trc1 plasmid is detailed to highlight the translational enhancer (ε) and the Shine-Dalgarno sequence (SD) which precede the coding region (black bar bracketed by NdeI and BsrGI sites). Restriction sites and coding regions for translation cassettes 1, 2, 3, 4 are shown in blue, green, yellow and red respectively. Transcriptional promoter and termination signals on pST50Trc1–4 are present but not shown. All restriction sites shown are unique. Plasmids are not drawn to scale.