Table 2.

Comparison of expression yields using the Tat or Sec export pathways.

POI	Signal peptidea	Yield (mg l−1)	Tat/Sec ratio (%)b	Reference
E. coliexpressionc
MBP	MBP	9.8	−	This study
	TorA(+10)	4.6	47	This study
	TorA(+6)	5.0	51	This study
	TorA(+0)	5.9	60	This study
GFP	PelB	nm	Nd	This study
	TorA	10–15	Nd	Barrett et al. (2003)
MBP–GFP	MBP	0.4	−	This study
	TorA	2.6	650	This study
scFv 26.10	PelB	1.0	−	Ribnicky et al. (2007)
	TorAd	0.1	12	Ribnicky et al. (2007)
scFv13.R4	MBP	0.01	−	This study
	TorA	0.06	600	This study
MBP–scFv13.R4	MBP	8.4	−	This study
	TorA	0.5	6	This study
Human tPA (truncated)	StII	140.0e	−	Kim et al. (2005)
	TorA	44.8e	29	Kim et al. (2005)
S. lividansexpressionf
S. lividansXlnB1	XlnB1g	nr	−	Gauthier et al. (2005)
	XlnCh	nr	33	Gauthier et al. (2005)
S. lividansXlnB2 (truncated)	XlnB1	nr	−	Gauthier et al. (2005)
	XlnC	nr	70	Gauthier et al. (2005)
S. equisimilisstreptokinase	Vsii	4	−	Pimienta et al. (2007)
	XlnC	0.1–0.2	4	Pimienta et al. (2007)
Human TNFa	Vsi	23.0	−	Schaerlaekens et al. (2004)
	XlnC	1.6	7	Schaerlaekens et al. (2004)
	XyyZj	1.4	6	Schaerlaekens et al. (2004)
Human IL‐2	Vsi	10.4	−	Schaerlaekens et al. (2004)
	XlnC	4.8	46	Schaerlaekens et al. (2004)

^a.All signal peptides derived from E. coliunless otherwise noted. Sec‐dependent signal peptides are listed in italics.

^b.Tat/Sec ratio calculated by dividing yield measured for Tat expression by the value measured for Sec expression. All values represent yield obtained from periplasmic or supernatant fraction.

^c.All proteins expressed in E. coliwere purified from the periplasm.

^d.Yields obtained using high‐cell E. colidensity fermentations.

^e.Expression via the Tat system was achieved using strain FÅ113 that has a more oxidizing cytoplasm than wild‐type strains of E. coli.

^f.All proteins expressed in S. lividanswere secreted and purified from the medium.

^g.Sec signal peptide derived from Streptomyces venezuelae xylanase B1 (XlnB1).

^h.Tat‐dependent signal peptide derived from S lividansxylanase C (XlnC).

^i.Signal peptide derived from S. venezuelaeCBS762.70 subtilisin inhibitor (Vsi).

^j.Signal peptide derived from S lividans tyrosinase (XyyZ).

nd, not determined; nm, not measurable (protein is completely undetectable); nr, not reported.