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From 2010.igem.org

Phototaxis

Progress report: We've gone back to our original idea for controlling phototaxis via a SRII/HtrII/EcTsr fusion-chimeric protein described in the following article,

[1] Photostimulation of a Sensory Rhodopsin II/HtrII/Tsr Fusion Chimera Activates CheA-Autophosphorylation and CheY-Phosphotransfer in Vitro† Vishwa D. Trivedi and, John L. Spudich Biochemistry 2003 42 (47), 13887-13892

which is shown to work in K-12 E. coli in this article,

[2] An Archaeal Photosignal-Transducing Module Mediates Phototaxis in Escherichia coli Jung, Kwang-Hwan, Spudich, Elena N., Trivedi, Vishwa D., Spudich, John L. J. Bacteriol. 2001 183: 6365-6371

- It works primarily by inducing autophosphorylation in CheA that in turn phosphorylates CheY into it's active state, that controls the flagellar switch.

- It is activated by blue light.

- CheY's effect on flagellar function is to increase the frequency of tumbling episodes.

Working Hypothesis: Right now our work with the Fusion-Chimeric photosensitive protein is oriented towards creating a negative feed-back regulation of our flow-generating system. We are working from the idea that inducing more frequent tumbling events in our bacterial colony will increase the amount of turbulence generated in our system, so as to reduce flow. Hereby we can control flow with light.

BioBrick Design: Since the fusion-chimeric protein is very large we will need to assemble it as a composite part. Luckily parts of it are connected by AA linker chains, we can exploit in our assembly, to reduce the effect of the BioBrick scar. Important considerations concerning staying in-frame and designing good BioBricks for assembly will be met in the coming days.

Note: We need to contact the original researchers on the mentioned papers for protein sequences and possibly plasmids or strains of their bacteria.

--CKurtzhals 19:38, 1 July 2010 (UTC)