Team:Hong Kong-CUHK/Project/background

Previous related projects - a review

In 2010 iGEM competition, Queens-Canada team submited halorhodopsin from H. salinarum as a biobrick and inserted this gene into C. elegans. However, it was not well characterized. This year, we are trying to clone halorhodopsin from N. pharaonis, which has already been successfully introduced and proved to perform complete light cycles in E. coli, to our biobrick system¹. We aim to characterize the efficiency of this halorhodopsin to be a well-documented biobrick and a useful tool in E. coli .

In previous iGEM projects, various light sensors have been developed, including red light sensor (UT Austin, 2004) and blue light sensor (University of Edinburgh, 2010). They are all light-induced fusion transcription factors that trigger gene expression under the control of specific promoters, facilitating simply on/off switch and light-coupled communication. However, our design makes halorhodopsin not only a dynamically tunable light sensor – by coupling with chloride sensitive promoters (e.g. P_gad), but also an energy converter – by converting solar energy as chemical potential and further turned it into electricity. Our project would provide a wilder scope of applications from signal transduction and gene regulation to energy harvesting.

References

1.        Hohenfeld, I. Purification of histidine tagged bacteriorhodopsin, pharaonis Halorhodopsin and pharaonis sensory rhodopsin II functionally expressed in Escherichia coli. FEBS Letters 442,198-202(1999).