<p>For in vivo characterization, we constructed candidate uTP sequences by concatenating the consensus sequences of discovered motif patterns. The uTP sequence classifiers were used to select the correct motifs for the fluorescent proteins we planned to use, mVenus and mNeonGreen. The two sequences with the highest confidence values (uTP1 and uTP2) were selected for in vivo experiments. These sequences were also submitted to the Parts Registry.</p>
<p>To further validate the constructed sequences, their predicted structure was examined. Structural prediction was performed on all 206 selected uTP-containing B. bigelowii proteins, to uncover the 3D conformation of uTP. The predicted structures were aligned and a consensus structure was created by averaging the aligned regions. This revealed a highly-conserved (stdev per residue position <1.8Å)structuralregionwith2alpha-helicesarrangedintoaU-bend(Fig5).ThestructureofconstructedmNeonGreenandmVenus+uTP1,uTP2sequenceswaspredictedandtheconsensusstructurealignedontothem,yieldinggoodalignment(RMSD<=4.0Å),confirmingthatourconstructswilllikelybehavesimilartonativeuTP-containingproteins.</p>
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<imgsrc="https://static.igem.wiki/teams/5054/msa.png"alt="Fig 1: Graphical overview of the experiment plan.">
<figcaption>Figure 5: Structural predictions. (a) Consensus structure of all uTP sequences extracted from UCYN-A imported proteins. (b) Consensus structure of all uTP sequences with charged residues shown (red=negative, blue=positive). (c) Consensus structure aligned onto uTP1 + mNeonGreen construct (RMSD=4.00Å). (d) Consensus structure aligned onto uTP2 + mNeonGreen construct (RMSD=3.77Å). </figcaption>
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<p>To allow the close study of UCYN-A by future iGEM teams and lay some groundwork for UCYN-A transplantation efforts, we developed a new, easier protocol for isolating it from a culture of B. bigelowii, compared to the known method reported by [1]. While Coale et al relied on a multistep procedure with a Percoll gradient and centrifugation, we used a sorting flow cytometer after lysing of the host cells. We confirmed UCYN-A’s presence in the isolate with PCR, with primers targeting part of the 16S rRNA gene exclusive to prokaryotes.
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<p>The isolates are not completely pure, as each of the three fractures contained UCYN-A. However, after comparing our cytometry plots with those from the literature, we hypothesize the third fracture to contain the densest sample of UCYN-A. This is supported by the relative intensity of the bands in the PCR gel, with the third lane being the strongest. This suggests the third population had the highest concentration of UCYN-A, since an equal amount of cells were collected in each sample and all PCR conditions were identical, meaning the intensity is approximately proportional to the amount of DNA in the starting sample.
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<p>For future investigation we would recommend the usage of qPCR in order to more precisely quantify the presence of UCYN-A DNA in different isolates.</p>
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<p>The successful fusion of E. coli into S. cerevisiae has been shown in literature before [5] using polyethylene glycol (PEG) to make the host cells permeable. As a first step we attempted to replicate these results. We used E. coli NCM3722 expressing PlsB-msGFP2 combined with fluorescent microscopy to validate the outcome of fusion. </p>
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<imgsrc="https://static.igem.wiki/teams/5054/bbigelowii.png"alt="Fig 1: Graphical overview of the experiment plan.">
<imgsrc="https://static.igem.wiki/teams/5054/PEG.png"alt="Fig 1: Graphical overview of the experiment plan.">
<figcaption><em>Scanning confocal images of a sample PEG fusion procedure (left) as well as a negative control containing regular yeast cells (right)</em>