Modification of CusSR bacterial two-component systems by the introduction of an inducible positive feedback loop.
The CusSR two-component system (TCS) is a copper-sensing apparatus of E. coli that is responsible for regulating the copper-related homeostatic system. The dynamic characteristics of the CusSR network were modified by the introduction of a positive feedback loop. To construct the feedback loop, the CusR, which is activated by the cusC promoter, was cloned downstream of the cusC promoter and reporter protein. The feedback loop system, once activated by environmental copper, triggers the activation of the cusC promoter, which results in the amplification of a reporter protein and CusR expression. The threshold copper concentration for the activation of the modified CusSR TCS network was lowered from 2,476.5 μg/l to 247.7 μg/l, which indicates a tenfold increase in sensitivity. The intensity of the output signal was increased twofold, and was maintained for 16 h. The strategy proposed in this study can also be applied to modify the dynamic characteristics of other TCSs.
School of Chemical Engineering and Bioengineering, University of Ulsan, 93 Daehakro, Nam-gu, Ulsan 680-749, Republic of Korea.
Sambandam
S
Ravikumar
Van Dung
VD
Pham
Seung Hwan
SH
Lee
Ik-Keun
IK
Yoo
Soon Ho
SH
Hong
D015374:Biosensing Techniques / Q000379:methods*; D003300:Copper; D004784:Environmental Monitoring; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005246:Feedback; D017930:Genes, Reporter; D005818:Genetic Engineering; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D011401:Promoter Regions, Genetic
C096350:CusC protein, E coli; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D003300:Copper