Part:BBa_K185033

An inverter of a special lactose operon system based on J23110-rbs34-lacI-dter-plac-rbs31

It is an inverter which its downsteam gene will always be repressed by lacI protein unless IPTG is added. And the synthetic rate of the downsteam gene is low because the low binding efficiency of B0031. This part improve on the basis of lac QPI system(BBa_K098986)

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  INCOMPATIBLE WITH RFC[12]

  Illegal NheI site found at 7
  Illegal NheI site found at 30
  
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  COMPATIBLE WITH RFC[25]
• 1000
  COMPATIBLE WITH RFC[1000]

Characterization of an inverter of lac system(BBa_K185033)

File:SJTU09 Result Overview5.jpg

It is an inverter which its downsteam gene will always be repressed by lacI protein unless IPTG is added. And the synthetic rate of the downsteam gene is low because the low binding efficiency of B0031.

And I choose to assemble BBa_I712019 with it. Here is the data

Sample	OD	RLUs1	RLUs1/OD
A1	2.64	8090131	3064444
A2	1.83	12033165	6575500
B1	2.74	14369947	5244506
B2	1.67	8374294	5014547
C1	1.79	34906168	19500653
C2	1.58	44358500	28075000
D1	0.7	59173888	84534126
D2	0.89	26208740	29448022
E	0.54	26208740	48534704
F	1.45	383217	264287.6

1. Sample A1/A2 are BL21 strain carrying BBa_K185033, induced by IPTG. for 5h.
2. Sample B1/B2 are BL21 strain carrying BBa_K185033, induced by IPTG. for 4h.
3. Sample C1/C2 are BL21 strain carrying BBa_K185033, induced by IPTG. for 2h.
4. Sample D1/D2 are BL21 strain carrying BBa_K185033, induced by IPTG. for 1h.
5. Sample E is BL21 strain carrying BBa_K185033, induced by IPTG. for 5min.
6. Sample F is BL21 strain carrying BBa_K185033, but it is not induced by IPTG.

Fig 5. Relationship between inducing time(t) and RLUs1/OD

From the data above, we know that the downstream genes (luciferase) are switched on sharply (about 100 times the uninduced sample) in the initial 1 hour. And then the synthesis of luciferase decreases into about 10 times the uninduced sample. It is certificated that our lac system is working.