The Expression of Soluble and Active Recombinant Haemophilus influenzae IgA1 Protease in E. coli

Table 2

Screening the expression of soluble IgA1 proteases by ELISA.

	Expression level (OD450)
	First round screening		Second round screening		Third round screening
Control					Negative control: C41(DE3) supernatant	0.08
			Positive control: purified IgA1 protease	0.21	Positive control: purified IgA1 protease	0.20
	Negative control: BL21(DE3) supernatant	0.10	Negative control: BL21(DE3) supernatant	0.08
Construct
	C41(DE3)	1.13	0.4 mM IPTG, 12 ° C	0.72	15°C, 0.2 mM IPTG	0.57
					15°C, 0.4 mM IPTG	0.72
			0.4 mM IPTG, 2 𝟎^∘ C	1.10	15°C, 0.6 mM IPTG	0.54
					20°C, 0.2 mM IPTG	0.87
			1 mM IPTG, 1 𝟐^∘ C	0.66	20°C, 0.4 mM IPTG	1.17
					20°C, 0.6 mM IPTG	1.02
			1 mM IPTG, 2 𝟎^∘ C	1.01	26°C, 0.2 mM IPTG	0.57
					26°C, 0.4 mM IPTG	0.51
					26°C, 0.6 mM IPTG	0.33
	Origami B(DE3)	0.98	0.4 mM IPTG, 12°C	0.36
			0.4 mM IPTG, 20°C	0.29
			1 mM IPTG, 12°C	0.35
			1 mM IPTG, 20°C	0.29
	BL21(DE3)	0.93	0.4 mM IPTG, 12°C	0.54
			0.4 mM IPTG, 20°C	0.59
pET-IGAN			1 mM IPTG, 12°C	0.49
			1 mM IPTG, 20°C	0.61
	Tuner (DE3)	0.92	0.4 mM IPTG, 12°C	0.48
			0.4 mM IPTG, 20°C	0.67
			1 mM IPTG, 12°C	0.46
			1 mM IPTG, 20°C	0.57
	BL21(DE3)pGro7	1.01	0.4 mM IPTG, 12°C	0.54
			0.4 mM IPTG, 20°C	0.73
			1 mM IPTG, 12°C	0.61
			1 mM IPTG, 20°C	0.47
	ArcticExpress (DE3)	1.00	0.4 mM IPTG, 12°C	0.68
			0.4 mM IPTG, 20°C	0.98
			1 mM IPTG, 12°C	0.70
			1 mM IPTG, 20°C	0.89
	KRX	0.56
	Origami B(DE3)pLysS	0.75
	C43 (DE3)	0.14
pET-S-IGAN	BL21(DE3)	0.90
	C41(DE3)	0.83
	C43(DE3)	0.20
	Origami B(DE3)	0.82
	KRX	0.73
	ArcticExpress(DE3)	0.85
	BL21(DE3)pGro7	0.86
	Tuner (DE3)	0.82
pCold-S-IGAN	BL21(DE3)	0.76
	C41(DE3)	0.70
	C43(DE3)	0.79
	Origami B(DE3)	0.70
	BL21(DE3)pGro7	0.44
pCold-IGAN	BL21(DE3)	0.56
	C41(DE3)	0.68
	C43(DE3)	0.15
	Origami B(DE3)	0.24
	BL21(DE3)pGro7	0.28