Coding

Part:BBa_K3165000

Designed by: Mohit Das   Group: iGEM19_IISc-Bangalore   (2019-10-17)
Revision as of 15:42, 17 October 2019 by Mohitdas (Talk | contribs) (Usage and Biology)


mini-CcaS

A miniaturized CcaS variant which lacks the two PAF domains, due to deletion of the segment following the GAF domain until the linker before the Histidine Kinase domain. Mini-CcaS as a green light-sensitive system has a much higher dynamic fold change (around 600) as compared to the protein complex found naturally in Synechocystis.



Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    COMPATIBLE WITH RFC[25]
  • 1000
    COMPATIBLE WITH RFC[1000]


Usage and Biology

Biology

CcaSR is a green-light activated two-component signal transduction system (TCS) that controls the expression of phycobilisome linker protein CpcG2 in Synechocystis PCC6803 complementary chromatic adaptation pathway. The naturally occurring CcaS protein is a cyanobacteriochrome sensor histidine kinase consisting of an N-terminal GAF domain (cGMP phosphodiesterase/ adenyl cyclase/ FhlA) bound to two PAS domains of unknown function attached to a C-terminal Histidine Kinase domain. Upon activation of green light, the CcaS switches to a red-absorbing conformation that phosphorylates the response regulator CcaR leading to the activation of the pCpcG2 promoter initiating transcription. On illumination with green light, a 6-fold activation of the protein was reported in the wild type protein. Mini-CcaS is a modified form of the naturally occurring CcaS protein which lacks the two PAS domains. The modified protein has highly reduced leakiness and a fold change of around 593, qualifying as a much more sensitive optogenetic system.

Usage

This part can be used to optically regulate the expression of the gene of interest downstream of the pCpcG2 promoter upon stimulation with the appropriate frequency of light. This part in association with the response regulator protein - CcaR can be used as a genetic circuit for optically programmed expression signals.


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Categories
Parameters
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