From 2007.igem.org

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Blue Photosensor Background

Method

This part is based on “Photostimulation of a Sensory Rhodopsin II/HtrII/Tsr Fusion Chimera Activates CheA-Autophosphorylation and CheY-Phosphotransfer in Vitro” by Vishwa D. Trivedi and John L. Spudich, Biochemistry 2003, 42, 13887-13892. Acording to this article the peak sensitivity is to 500+/-5nm, and results in a 3 fold activation of the Tsr.. CheA,W,Y connected system.

It is proposed to replace Tsr with homolgouse CopP. SRII-HtrII fusion to which CopP is fused CopA when phosphorylated by CopP is an activator for PsfA promoter sequence from Dr Alan Grossman (M.I.T.) Based on

• SRII-HtrII-Tsr fusion from Prof J.L. Spudich (university of Texas)melb:spudich N sequence
• BBa_J51000 (ComP) kinase
• BBa_J51001 (ComA) activator

PARTS:

• SrfA promoter
• ComA protein generator
• SRII-ComP photosensor
• Any phyco construction genes?

SRII is from Natronomonas pharaonis.

Tsr fusion was made by Jung et al J Bacteriol 183 6365-6371 (2001) they propose a mechanism. I don’t see why anyone thinks this will work!!! Currently a conformational change induced by light increases affinity in TSR for Che family which leads to cross phosphorylation. To replace TSR with a kinase would require the kinase activity to be modulated – hence matching using homology as was done for tsr is not likely to work. Also what are the normal functions of ComP etc.