Part:BBa_K3165000
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
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE 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
| None |