Skip to main content

Table 1 Comparison of different promoter modified strategies

From: Development of a Fur-dependent and tightly regulated expression system in Escherichia colifor toxic protein synthesis

Strategy

Modified strategies and descriptions

Repression RF

Induction RF

Induction ratio

Relative induction fold

NC

E. coli Top10

200 ± 10

200 ± 9

0

1

PC

PBAD

260 ± 11

7812 ± 31

126

30

0

Original fhuA promoter

3292 ± 20

10116 ± 37

3

51

1

Changed the Fur box in −10 region into a conserved Fur box from E. coli[17]

250 ± 12

5466 ± 26

101

27

2

Modified the Fur box in −10 region into an enhanced Fur box [17]

196 ± 5

1885 ± 17

BDL

9

3

Integrated a designed Fur box in −35 region

200 ± 9

662 ± 19

BDL

3

4

Inserted the SD-fur-TT circuit in the vector

230 ± 9

3464 ± 24

108

17

5

Inserted the Pfur-SDfur-TT circuit in the vector

195 ± 7

2389 ± 26

BDL

12

  1. Repression RF = Relative fluorescence units under repression condition (LB + 40 μM FeSO4);
  2. Induction RF = Relative fluorescence units under induction condition (LB + 200 μM 2,2’-dipyridyl);
  3. Induction ratio = (Induction RF – NC’s Induction RF)/ (Repression RF- NC’s Repression RF), indicating the tightness of promoter;
  4. Relative induction fold = Induction RF/NC’s Induction RF, indicating the transcription efficiency of promoter;
  5. BDL, beyond detection limit; NC, Negative control; PC, Positive control.