Difference between revisions of "Part:BBa K2638200"
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==Results==
 
==Results==
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<img src="https://static.igem.org/mediawiki/2018/0/08/T--Bielefeld-CeBiTec--wellplate_vk.png" style="width:100%">
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</div>
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              <div class="sidenavi" id="side_bar">
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<li class="side_list">
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<a href="#toxa">Toxicity Assays</a>
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</li>
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<li class="side_list">
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<a href="#memb">Membrane Permeability Assays</a>
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</li>
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<li class="side_list">
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<a href="#spec">Specific Uptake Assay</a>
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                        <li class="side_list">
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        <div class="main_content">
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<div class="title">Accumulation Results</div>
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<h2>Short Summary</h2>
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<article>To test whether our accumulation system with the importers <i>oprC</i>, <i>hmtA</i>, <i>copC</i> and <i>copD</i> works as intended, we conducted several experiments analyzing Cu(II) ion uptake. We conducted growth experiments and observed hindered cell growth when expressing our transporter proteins, which indicates import of toxic copper into the cell. Furthermore, we measured membrane permeability thereby, showing the ion channel nature of the transporter proteins in the outer membrane. Finally we showed the proteins specifity for taking up Cu(II).</article>
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<a name="toxa" id="toxa" class="shifted-anchor"></a>
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<h2>Toxicity Assays</h2>
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<div class="article">
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As intracellular copper leads to toxic effects in the cell (read more on our <a href="http://2018.igem.org/Team:Bielefeld-CeBiTec/Toxicity_Theory" target="_blank">toxicity</a>) page, an increased uptake of Cu(II) ions should slow down and exacerbate cell growth. Therefore, we examined the growth of <i>E. coli</i> KRX expressing <i>oprC</i> in lysogeny broth (LB) media with 30 ng/µL chloramphenicol supplemented with different concentrations of CuSO<sub>4</sub> (0 mM, 1 mM, 2 mM, 3 mM, 4 mM, 8 mM) by measuring the optical density at a wavelength of 600 nm (OD600). As a control we decided to use the pSB1C3 null vector under same conditions as well. The measurement was performed with the <a href="https://lifesciences.tecan.com/plate_readers/infinite_200_pro" target="_blank"> Infinite® 200 PRO</a> in a 24 wellplate with flat bottom (Greiner&reg;). For expression of the BioBricks either a T7 promoter and a ribosome binding site (RBS) (BBa_K525998) or a combination of the <i>pBAD/araC</i> promoter (BBa_I0500) and a RBS (BBa_B0030) (RBS) were cloned upstream of (<i>oprC</i> (BBa_K2638200).
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<article>All toxicity measurements were performed by inoculating <i>E. coli</i> KRX cultures harbouring the plasmid of interest with a starting OD600 of 0.01 from an overnight culture. Afterwards cells were grown (37 °C, 350 rpm) for 3 h and were induced either with 0.1 % rhamnose and 0.1 mM IPTG for the T7 constructs or 1 % arabinose for the arabinose constructs. The OD600 of the cultures were measured every hour for up to 12 hours.
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<br><br>
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The growth of <i>E. coli</i> KRX expressing <i>oprC</i> (BBa_K2638201) after induction in comparison showed lower maximum cell densities, even in the culture without added Cu(II). This effect is a consequence of the high metabolic burden bearing on the cells due to strong expression of the T7 promoter controlled genes. When growing in copper-containing media the cells expressing <i>oprC</i> show a stronger growth inhibition. This effect gets stronger with increasing Cu(II) concentrations. Especially interesting is the growth curve progression at a concentration of 2 mM Cu(II) (figure 1). The optical density does not only increase at a reduced rate, it even decreases after approximately 220 minutes, which indicates cell death. Both growth inhibitions cannot be observed with <i>E. coli</i> carrying pSB1C3.</article>
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<div class="article">The NPN assay is a easy and fast method to measure membrane permeability.
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In both strains which expressed the composite parts <a href="https://parts.igem.org/Part:BBa_K2638201" target="_blank">BBa_2638201</a> and <a href="https://parts.igem.org/Part:BBa_K2638004" target="_blank">BBa_K2638204</a> a higher increase in fluorescence than the pSB1C3 controll strain was measurable.
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</div>
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<article>An <i>orhto</i>-Nitrophenyl-&beta;-galactoside (ONPG) assay was performed with eight different pSB1C3 constructs to show that our copper transport Biobricks do not unspecifically take up different substrates.
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In both strains which expressed the composite parts <a href="https://parts.igem.org/Part:BBa_K2638201" target="_blank">BBa_2638201</a> and <a href="https://parts.igem.org/Part:BBa_K2638004" target="_blank">BBa_K2638204</a> a higher increase in fluorescence than the pSB1C3 controll strain was measurable.
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</article>
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===Overview===
 
===Overview===
 
*<p align="justify">Upon expression of the outer membrane transport protein OprC [http://2018.igem.org/Team:Bielefeld-CeBiTec/Accumulation_Results] combined with different membrane permeability assays and uptake assays.
 
*<p align="justify">Upon expression of the outer membrane transport protein OprC [http://2018.igem.org/Team:Bielefeld-CeBiTec/Accumulation_Results] combined with different membrane permeability assays and uptake assays.

Revision as of 03:47, 18 October 2018


OprC (TonB dependent copper transport porin)

OprC is an outer membrane porin which binds and transports specifically copper. It belongs to the the superfamily of the TonB-dependent transporters. This variant of OprC was taken from Pseudomonas brassicacearum 3Re2-7 13, a not yet published strain.


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
    INCOMPATIBLE WITH RFC[25]
    Illegal NgoMIV site found at 252
    Illegal NgoMIV site found at 583
    Illegal NgoMIV site found at 787
    Illegal NgoMIV site found at 1831
    Illegal NgoMIV site found at 2032
    Illegal AgeI site found at 246
  • 1000
    COMPATIBLE WITH RFC[1000]