Difference between revisions of "Part:BBa K2862008"

Revision as of 07:14, 17 October 2018

pSoxS Mutant 1

pSoxS is one half of the pSoxR/pSoxS bidirectional promoter. Transcription downstream of pSoxS is activated in response to oxidation of the SoxR transcription factor, either directly by redox-cycling drugs or by oxidative stress. It is therefore inducible by various redox-cycling drugs, toxins, antibiotics, heavy metals, hydrogen peroxide and nitric oxide: providing various applications in the development of environmental and therapeutic devices. By coupling oxidation of redox-cycling species to an electrode, the 2018 Imperial College London iGEM team (PixCell) used pSoxS to build electrogenetic devices where electrical inputs modulated gene expression.

This pSoxS promoter was taken from E. coli with mutations being introduced at the -35/-10 site in order to introduce more common nucleotides to increase promoter activity. The promoter was also engineered to be unidirectional by knocking out activity of the pSoxR portion. It was designed with an upstream terminator to remove the need for these to be added as parts in large assemblies. It also contains a downstream ribozyme to reduce context-dependency. It forms part of the PixCell library of electrogenetic and redox-sensing parts.

This part is compatible for BioBrick, BASIC and Golden Gate assembly.

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
INCOMPATIBLE WITH RFC[1000]
Illegal BsaI site found at 49
Illegal BsaI.rc site found at 286

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 <partinfo>BBa_K2862008 short</partinfo>
-Pfam1-pSox-4 is a promoter
+pSoxS is one half of the pSoxR/pSoxS bidirectional promoter. Transcription downstream of pSoxS is activated in response to oxidation of the SoxR transcription factor, either directly by redox-cycling drugs or by oxidative stress. It is therefore inducible by various redox-cycling drugs, toxins, antibiotics, heavy metals, hydrogen peroxide and nitric oxide: providing various applications in the development of environmental and therapeutic devices. By coupling oxidation of redox-cycling species to an electrode, the 2018 Imperial College London iGEM team (PixCell) used pSoxS to build electrogenetic devices where electrical inputs modulated gene expression.
+This pSoxS promoter was taken from E. coli with mutations being introduced at the -35/-10 site in order to introduce more common nucleotides to increase promoter activity. The promoter was also engineered to be unidirectional by knocking out activity of the pSoxR portion. It was designed with an upstream terminator to remove the need for these to be added as parts in large assemblies. It also contains a downstream ribozyme to reduce context-dependency. It forms part of the PixCell library of electrogenetic and redox-sensing parts.
+This part is compatible for BioBrick, BASIC and Golden Gate assembly.
 <!-- Add more about the biology of this part here
 ===Usage and Biology===
+pSoxS is the cognate transcription factor to the SoxR trasncription factor and one half of the pSoxR/pSoxS bidirectional promoter. When SoxR is reduced the promoter is inactive whereas upon its oxidation by redox-cycling drugs or oxidative stress it provides transcriptional activation downstream of pSoxS. This allows for activation of the soxRS regulon which allows for adaptation to conditions of oxidative stress. Although SoxR is able to bind pSoxS in both its oxidised and reduced forms, only the oxidised form provides transcriptional activation.
+The promoter is conserved amongst various species of both gram-positive and gram-negative bacteria. A long 19bp spacer region between the -10 and -35 consensus sequences (16-18bp is standard) allows for the promoter to be constitutively inactive. Crystallographic data shows that interactions between oxidised SoxR and the spacer is reduced in length by ~3.4Å, the equivalent of ~1bp, thereby returning the spacer region to a more standard length. This allows for transcription to occur from the promoter, demonstrating the promoters mechanism of transcriptional activation. Previous papers proved how deletions of 2bp from the spacer region can manipulate this mechanism to create a constitutively active promoter with induction causing transcriptional repression due to shortening of the spacer region past the threshold for activity. Transcriptional activation downstream of pSoxS allows for activation of the soxRS regulon which in turns provides adaptation to conditions of oxidative stress.
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