Team:Freiburg/Description

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==<span style="color:grey;">Precipitator</span>==
==<span style="color:grey;">Precipitator</span>==
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|[[File:Freiburg11_Precipitator_scheme.png|200px]]
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Precipitator binding a polystyrene surface with the plastic binding domain and a His-tagged Protein via Nickel ions
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===The Concept===
===The Concept===
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<span style="color:green;">'''artifical LRR domain fragment'''<br></span>'''
<span style="color:green;">'''artifical LRR domain fragment'''<br></span>'''
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|[[Image:HURRRRGH.png|200px]]
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Precipitator binding a polystyrene surface with the plastic binding domain and a His-tagged Protein via Nickel ions
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This protein can be used to complex Nickel or Cobalt. Histidines are positioned in such a way, that they can coordinate the ions
This protein can be used to complex Nickel or Cobalt. Histidines are positioned in such a way, that they can coordinate the ions
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==Plastic binding domain==
==Plastic binding domain==
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'''One of the issues of our project „lab in a cell“ was to use endogenous proteins produced by the cell itself for specific purification and hereby to replace expensive columns. The „precipitator“ designed by our team contains a protein binding domain which complexes nickel and thus enables the binding of His-tagged proteins. After cell lysis the “precipitator” is freely dissolved in the cell lysate. To be able to isolate the “precipitator”-His-tagged-protein-complex from the other cell components it has to be immobilized by another protein domain. The part we designed for this function is the so-called plastic binding domain.'''
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One of the issues of our project „lab in a cell“ was to use endogenous proteins produced by the cell itself for specific purification and hereby to replace expensive columns. The „precipitator“ designed by our team contains a protein binding domain which complexes nickel and thus enables the binding of His-tagged proteins. After cell lysis the “precipitator” is freely dissolved in the cell lysate. To be able to isolate the “precipitator”-His-tagged-protein-complex from the other cell components it has to be immobilized by another protein domain. The part we designed for this function is the so-called plastic binding domain.
During routine phage display of random peptide libraries, phages were found that bound directly to the plastic surface of the used plastic micro titer plates. The number of plastic binding phages obtained during the phage display experiments depended on the saturation of the plastic micro titer plates with target protein for the antibody-binding phages and could be reduced by the use of blocking proteins as BSA or non-fat milk. Plastic binding phages were resistant to washing steps with PBS alone as well as to PBS in combination with BSA or non-fat dry milk. It was shown that plastic binding phages were even more difficult to recover by acid elution than the “normal” antibody binding phages (Adey et al., 1995).  
During routine phage display of random peptide libraries, phages were found that bound directly to the plastic surface of the used plastic micro titer plates. The number of plastic binding phages obtained during the phage display experiments depended on the saturation of the plastic micro titer plates with target protein for the antibody-binding phages and could be reduced by the use of blocking proteins as BSA or non-fat milk. Plastic binding phages were resistant to washing steps with PBS alone as well as to PBS in combination with BSA or non-fat dry milk. It was shown that plastic binding phages were even more difficult to recover by acid elution than the “normal” antibody binding phages (Adey et al., 1995).  
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We decided to use light-controlled gene expression, because light is everywhere and always available.<br/>
We decided to use light-controlled gene expression, because light is everywhere and always available.<br/>
The green light receptor is a light-sensing system from the cyanobactrium  ''Synechocystis sp.'' PCC6803.<br/> It consists of three parts interacting with each other in order to start regulated gene expression.<br/> These parts are the following:
The green light receptor is a light-sensing system from the cyanobactrium  ''Synechocystis sp.'' PCC6803.<br/> It consists of three parts interacting with each other in order to start regulated gene expression.<br/> These parts are the following:
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The main receptor is  CcaS(1), a cyanobacteriochrome, which shows increased autophosphorylation after exposure to green light. The protein CcaS is made up of a N-terminal transmembrane helix, a cyanobactreria specific  GAF domain, two PAS domains and a C-terminal histidine kinase.(Yuu Hirose et al. ( 2008 ))  
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The main receptor is  CcaS(1), a cyanobacteriochrome, which shows increased autophosphorylation after exposure to green light. The protein CcaS is made up of a N-terminal transmembrane helix, a cyanobactreria specific  GAF domain, two PAS domains and a C-terminal histidine kinase.(Yuu Hirose et al.)  
To be fully functional CcaS has to bind the chromophore Phycocyanobilin (PCB) with its GAF-domain.  
To be fully functional CcaS has to bind the chromophore Phycocyanobilin (PCB) with its GAF-domain.  
The GAF domain in this system has the ligation motif Cys-Leu, instead of the usual plant GAF-domain with Cys-His.
The GAF domain in this system has the ligation motif Cys-Leu, instead of the usual plant GAF-domain with Cys-His.
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|[[File:Green light system.jpg|350px]]
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After light of the wavelength of 532 nm is exposed to the CcaS receptor, it changes its conformation. It undergoes autophosphorylation and the phosphate is transfered to the response regulator CcaR. Once phosphorylated, CcaR can bind to the specific promoter region of cpcG and activate gene expression.
After light of the wavelength of 532 nm is exposed to the CcaS receptor, it changes its conformation. It undergoes autophosphorylation and the phosphate is transfered to the response regulator CcaR. Once phosphorylated, CcaR can bind to the specific promoter region of cpcG and activate gene expression.
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As the green light sensing system from the cyanobacteria ''Synechocystis sp.'' PCC6803  was proven by J. J. Tabor to work also in ''E. coli'', our plan is to integrate the genes for CcaS and CcaR into ''E. coli'' genome with a BAC (bacterial artificial chromosome). The researchers gene of interest just needs to be inserted behind the cpcG2 promoter region and transferred into "our" ''E .coli'' strain to become green light inducible.
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As the green light sensing system from the cyanobacteria ''Synechocystis sp.'' PCC6803  was proven by J. J. Tabor to work also in ''E. coli'', our plan is to integrate the genes for CcaS and CcaR into ''E. coli'' genome with a BAC (bacterial artificial chromosome). The researchers gene of interest just needs to be inserted behind the cpcG2 promoter region and transferred into "our" ''E .coli'' strain to become green light inducible.
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|[[File:Freiburg2011_greenlight_DNA.jpg|500px]]
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Green light system
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References:
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'''References:'''
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Nils B. Adey et al. 1995 <br/>
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Nils B. Adey et al. 1995 “Characterization of phage that bind plastic from phage-displayed random peptide libraries”
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“Characterization of phage that bind plastic from phage-displayed random peptide libraries” <br/>
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Gene 156 (1995) 27-31 <br/>  
Gene 156 (1995) 27-31 <br/>  
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Alfredo Menendez & Jamie K. Scott 2005 <br/>
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Alfredo Menendez & Jamie K. Scott 2005 “The nature of target-unrelated peptides recovered in the screening of phage-displayed random peptide libraries with  antibodies”
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“The nature of target-unrelated peptides recovered in the screening of phage-displayed random peptide libraries with  antibodies” <br/>
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Anal. Biochem. 336 (2005) 145-157 <br/>  
Anal. Biochem. 336 (2005) 145-157 <br/>  
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L. A. Cantarero et al. 1980 <br/>
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L. A. Cantarero et al. 1980
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“The absorptive characteristics of proteins for polystyrene and their significance in solid phase immunoassays” <br/>
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“The absorptive characteristics of proteins for polystyrene and their significance in solid phase immunoassays”  
Anal. Biochem. 105 (1980) 375-382 <br/>
Anal. Biochem. 105 (1980) 375-382 <br/>
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Ry Young et al<br/>
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Ry Young et al. 2000
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“Phages will out: strategies of host cell lysis”<br/>
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“Phages will out: strategies of host cell lysis”
Trends in Microbiology Vol 8, Issue 3 (2000) 120-128<br/>
Trends in Microbiology Vol 8, Issue 3 (2000) 120-128<br/>
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Joel Berry et al<br/>
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Joel Berry et al. 2008
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“The final step in the phage infection cycle: the Rz and Rz1 lysis proteins link the inner and outer membranes”<br/>
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“The final step in the phage infection cycle: the Rz and Rz1 lysis proteins link the inner and outer membranes”
Molecular Microbiology 70 (2008) 341–351<br/>
Molecular Microbiology 70 (2008) 341–351<br/>

Latest revision as of 03:51, 22 September 2011


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of the Freiburger student
team competing for iGEM 2011.
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