Difference between revisions of "Team:Aix-Marseille/Results"
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<p>The laccase coupled with the X compound can oxidize the styrene (FIG.4). Replacing the X compound by the cytochrome C, we don’t observe a decreased dioxygen concentration and then the polymer degradation (FIG.4).</p> | <p>The laccase coupled with the X compound can oxidize the styrene (FIG.4). Replacing the X compound by the cytochrome C, we don’t observe a decreased dioxygen concentration and then the polymer degradation (FIG.4).</p> | ||
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<span><p class="space20"><div align="justify"><span style ="font-family:Courier New">Figure 3: Putative schema of reaction with the laccase and the cytochrom C</span><br /><br /> | <span><p class="space20"><div align="justify"><span style ="font-family:Courier New">Figure 3: Putative schema of reaction with the laccase and the cytochrom C</span><br /><br /> | ||
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Revision as of 11:38, 17 September 2015
Production of Laccase E.coli
To obtain our Laccase E.coli, we used the BioBrick Bba_K863006 and we removed its stop codon. Then we added to this BioBrick a promoter and a His-Tag.
Thanks to digestion, ligation and transformation, we managed to get our BioBrick named “01-35-02” with a size of about 1700 pb:
Figure A: Schematic representation of “01-35-02”
Figure A: Schematic representation of “01-35-02”
Figure B: Digestion from “01-35-02” miniprep to check the size of the insert
The band corresponds to the expected size for the insert, which is about 1700 pb.”
Figure C: Western Blot of the expression of “01-35-02” into E. coli
The expected size of the protein is about 53 kDa.
Laccase T.thermophilus from iGEM parts
To get our Laccase T. thermophilus, we used the BioBrick Bba_K863011 and we removed its stop codon.
Then we tried to add to this BioBrick a promoter and a His-Tag.
Unfortunately we managed to add only the promoter.
Figure A: Schematic representation of “01-35-02”
Then we inserted our BioBrick into E.coli strain (BL21) to express it. We induced it by addition of IPTG into the cell culture. We made a Western-Blot using a primary antibody against the His-tag and an anti-mouse secondary antibody conjugate with HRP (horseradish peroxidase). The expected size of the protein “01-35-02” is 53 kDa.
Then we tried to add to this BioBrick a promoter and a His-Tag.
Unfortunately we managed to add only the promoter.
Figure A: Schematic representation of “01-35-02”Then we inserted our BioBrick into E.coli strain (BL21) to express it. We induced it by addition of IPTG into the cell culture. We made a Western-Blot using a primary antibody against the His-tag and an anti-mouse secondary antibody conjugate with HRP (horseradish peroxidase). The expected size of the protein “01-35-02” is 53 kDa.
Figure E: Digestion from “01-36” miniprep to check the size of the insert
The band corresponds to the expected size for the insert, which is about 1500 pb.”
Laccase T.thermophilus from IDT
We ordered from IDT a laccase optimized for an expression into E.coli.
From this optimised laccase, we added a promoter and a His-Tag.
This new BioBrick is named “01-30-02” with an expected size of about 1500 pb
Figure A : Schematic representation of “01-30-02”
From this optimised laccase, we added a promoter and a His-Tag.
This new BioBrick is named “01-30-02” with an expected size of about 1500 pb
Figure A : Schematic representation of “01-30-02”
Figure B: Digestion from “01-30-02” miniprep to check the size of the insert
The band corresponds to the expected size for the insert, which is about 1500 pb.
Enzymatic activity
All tests were performed using laccases and cytochromes C obtained by ISM2 (Institut des Sciences Moléculaires de Marseille)and LISM (Laboratoire d’Ingénierie des Systèmes Macromoléculaires)).
Question 1: Can the laccase oxidize the cytochrome C?
To answer this question, we used absorbance properties of the cytochrome C (FIG.1). Indeed, the reduced cytochrome C (curve in red) absorbs at 550 nm whereas the oxidized cytochrome C (curve in green) doesn’t absorb. By spectrophotometry, we analyzed the change in oxidation state. When the cytochrome C is alone, we don’t observe oxidation (FIG.2, blue curve). When we add the laccase, the cytochrome C oxidizes as we can see a decreased absorbance at 550 nm (FIG.2, red curve). We can see the effect of the laccase on the cytochrome C.
Figure 1 : Absorbance propertiez of cytochrome C
Figure 2: Oxydation of cytochrom C by laccase
Conclusion 1: The laccase can oxidize the cytochrome C.
Question 2: Can the cytochrome C and the laccase oxidize chewing-gum polymer?
The aim of our project is to show that the chewing gum can be degraded by the laccase and the cytochrome C in presence of the light.
Using the X compound, the light and the laccase, the styrene that is a close chewing gum polymer can be oxidized (FIG.3 & FIG.4). The X compound is a rare metal so we don’t want to use it.
Hypothesis: Could the cytochrome C substitute the X compound to oxidize the styrene?
To test our hypothesis, we used an oxygraph. This engine allows us to measure dioxygen concentration consumed during the reoxidation of the X compound or the cytochrome C by the laccase.
The laccase coupled with the X compound can oxidize the styrene (FIG.4). Replacing the X compound by the cytochrome C, we don’t observe a decreased dioxygen concentration and then the polymer degradation (FIG.4).
Figure 3: Putative schema of reaction with the laccase and the cytochrom C
Figure 2: Oxydation of cytochrom C by laccase
