Team:Calgary/Project/IbpAB
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<span id="bodytitle"><h1>Cytoplasmic Stress Detectors</h1></span> | <span id="bodytitle"><h1>Cytoplasmic Stress Detectors</h1></span> | ||
- | <h2> | + | <h2>How does protein misfolding occur?</h2> |
- | + | <p>Protein misfolding can occur as a result of several factors. It can be | |
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due to overproduction of the protein in the cell, in which case the cell | due to overproduction of the protein in the cell, in which case the cell | ||
lacks resources such as chaperones to fold the protein fast enough. This | lacks resources such as chaperones to fold the protein fast enough. This | ||
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are different in the two cellular compartments.</p> | are different in the two cellular compartments.</p> | ||
- | <p> | + | <h2>How does a native <i>E. coli</i> cell combat protein related stress?</h2> |
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There are several heat shock pathways in E. coli which are actively | There are several heat shock pathways in E. coli which are actively | ||
transcribed in response to cellular stress. This class of proteins are | transcribed in response to cellular stress. This class of proteins are | ||
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responsible for refolding aggregated bodies and inclusion bodies into | responsible for refolding aggregated bodies and inclusion bodies into | ||
their native conformation.</p> | their native conformation.</p> | ||
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+ | <h2> iGEM Calgary cytoplasmic stress detection circuit</h2> | ||
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+ | <img src="http://i872.photobucket.com/albums/ab287/iGEMCalgary_2010/ibpab-1.png"></img> </td> | ||
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+ | <td> The cytoplasmic stress detector has a fusion of sigma 32 activated heat shock promoter which allows a higher output compared to the ibpAB promoter and FxsA promoter </td> | ||
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+ | </tr> | ||
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+ | </table> | ||
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<p> | <p> |
Revision as of 08:25, 27 October 2010
![University of Calgary iGEM Team 2010](http://i872.photobucket.com/albums/ab287/iGEMCalgary_2010/Header4.png)
Cytoplasmic Stress Detectors
How does protein misfolding occur?
Protein misfolding can occur as a result of several factors. It can be due to overproduction of the protein in the cell, in which case the cell lacks resources such as chaperones to fold the protein fast enough. This can cause the proteins to misfold and form aggregate bodies. Proteins can also misfold due to mutations that occur in the coding region of the protein that can alter the amino acid sequence and thereby interrupting the native structure of the protein, causing it to misfold and be dysfunctional. Proteins can also misfold due to cellular stress such as a change in pH, temperature and change in media. Due to lack of optimal folding conditions proteins can form aggregate bodies and cause activation of heat shock systems, chaperone systems and proteolytic pathways which are involved in either refolding the proteins into their native form or degrading the aggregate bodies. Proteins can also misfold due to lack of localization. For example: if a periplasmic protein lacked a signal sequence it will misfold in the cytoplasm because the conditions are different in the two cellular compartments.
How does a native E. coli cell combat protein related stress?
p> There are several heat shock pathways in E. coli which are actively transcribed in response to cellular stress. This class of proteins are called small heat shock proteins (sHsps). sHsps consist of proteins such as ibpA, ibpB, DnaK, DnaJ, GroEL and GroES. Amongst these, IbpA and ibpB are two different proteins that are activated as a result of cytoplasmic stress response. IbpA and ibpB proteins are chaperones that are responsible for refolding aggregated bodies and inclusion bodies into their native conformation.iGEM Calgary cytoplasmic stress detection circuit
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The cytoplasmic stress detector has a fusion of sigma 32 activated heat shock promoter which allows a higher output compared to the ibpAB promoter and FxsA promoter |
In our cytoplasmic stress detector circuit, we decided to fuse two different promoter regions from two heat shock proteins, which are ibpAB and fxsA. In a study done by Kraft et al, they demonstrate that a fusion of IbpAB/fxsA promoters combined along with T7 DNA has a significantly higher output as a result of heat shock compared to the promoters individually.