Figure 3.

The effect of co- vs pre-expression of folding factors on the production of vtPA in the cytoplasm of E. coli. Relative yields of active MBP-vtPA produced in LB media at 30°C, normalized to the equivalent of the best previously reported system (a Δgor ΔtrxB strain with co-expression of mature DsbC) and shown as mean ± s.d. (n = 4-12; see additional file 1: Table of vtPA production and activity data). Strains: RG = rosetta-gami; OG = origami. For Erv1p and mature DsbC expression + = co-expression while +p = pre-expression. Note the increase in vtPA activity with pre-expression comes despite the significant reduction in vtPA expression levels in rosetta-gami compared with origami due to the expression of rare tRNAs (figure 1B).