Team:Bordeaux/Parts

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Synthesis of the gene coding for the SLPs(BBa_K1317002)

BBa_K1317001

Initial strategy :

We tried to assemble the gene coding for the SLPs from 8 oligonucleotids with homolog regions with the Gibson Assembly.
First of all, consensus sequences for the spider silk were identified and our own protein was designed. Then, the nucleotidic sequence using the peptidic sequence was determined. We had to pay attention because our proteic sequence is made of repeted motifs.



Table 1 : sequences of the 8 nucleotides

2 different methods were used with the Gibson Assembly1: in one step at 50°C or with cycles of denaturation at 95°C and annealing at 50°C (figure 1). The enzyme used was the Phusion® High Fidelity Polymerase.



Figure 1: Strategy of the Gibson Assembly to assemble the gene coding for the SLPs

Our 8 oligo weren’t assembled with these 2 methods, so another method was used : the PCR-Fusion2.
This method is made of different steps using the Phusion® High Fidelity Polymerase (picture 2). In a first step fragments were joining two by two, then fragments 1-2 were joined to fragments 3-4 and a PCR is achieved using fragments 1 and 4 as primers. The same method was used for fragments 5-6 and 7-8.
Finally, fragments 1-2-3-4 were assembled to fragments 5-6-7-8 and a PCR was also achieved using the fragments 1 and 8 as primers.



Figure 2: PCR Fusion strategy to assemble the gene coding for the SLPs

This method wasn’t successful because fragments 6 and 7 were unable to join. Therefore, new fragments were designed with a different homolog region. The fragment 8 that added only 2 nucleotids was suppressed and these 2 nucleotids were added on fragments 7.



Table 2: Sequence of the new fragments

Then, a new strategy was used (picture 3). The two first steps are common but then, fragments 5-6 are joined to fragments 1-2-3-4 and the PCR is made with the fragments 1 and 6. Finally the fragment 7 is added and a PCR is also achieved.



Fig 3 : Strategy to assemble the CDS for the SLPs using the new fragments 6 and 7

This method enable the assembly of the 7 fragments (picture 4). A fragment of 318 bp was expected on the electrophoresis gel.



Figure 4 : Gel electrophoresis on 3% agarose

Reference :



[1] https://www.neb.com/tools-and-resources/feature-articles/gibson-assembly-building-a-synthetic-biology-toolset

[2] Shevchuk N.A., Bryksin A.V., Nusinovich Y.A., Cabello F.C., Sutherland M. et Ladisch S. Construction of long DNA molecules using long PCR-based fusion of several fragments simultaneously (2004) Nucleic Acids Res., 32(2), 19



Part:BBa_K1317001 : CDS for resilin-like polypeptide (RLP)

This part is the coding sequence for the resilin like polypeptide. This sequence was assembled from a consensus of the proresilin exon 1 from Drosophila melanogaster. This protein, in insects, allows resistance and elasticity used for jumping, flapping... The synthetic gene encodes a synthetic protein "resilin-like". The repeated aminoacids allow to retrieve these properties of resistance, resilience and elasticity, but with a minimal pattern of the original protein, which is more suited for downstream applications. It can be used to produce wire presenting these properties after wet-spinning.

Sequence and Features



Design Notes

The gene used to assemble the biobrick has been provided by GenScript even if the assembling strategy succeeded It allows us to have the proper sequence without mutation and with sequencing results.
The strategy of our assembly is described below anyway. The gene was synthesized by ordering specific oligo with overlapping regions, and by adding a NheI site for further fusing proteins.
We used the pro-resilin exon 1 from Drosophila melanogaster. We identified a repetitive pattern, PSXXYGAP. So we blast it against the protein database of pro-resilin to check if the pattern was conserved within different species or specific to Drosophila.



We have taken XX randomly and we brought out conserved pattern so we used it to do our resilin like polypeptide with the following pattern: (RLP) MW-[(PSSSYGAP)(PSNSYGAP)(PSTSYGAP)(PVAYGAP)]3

The literature delivers some mechanical properties concerning native resilin as high resilience (<90%) that allows the protein to recover its initial folding after a high tensile stress. Thus it can be an interesting characteristic to show and use, so we wanted to test it on our RLP.

Source

Genomic sequence from Drosophila melanogaster

References

[1] Tamburro A.M. et al. Molecular and supramolecular structural studies on significant repetitive sequences of resilin (2010) Chembiochem., 11(1), 83-93. doi: 10.1002/cbic.200900460.
[2] Linqing Li et Kristi L. Kiick. Resilin-Based Materials for Biomedical Applications (2013) ACS Macro Lett., 2(8), 635–640. doi: 10.1021/mz4002194.
[3] David H. Ardell and Svend Olav Andersen Tentative identification of a resilin gene in Drosophila melanogaster Insect Biochemistry and Molecular Biology 31 (2001) 965–970
[4] Julie N. Renner et al. Characterization of Resilin-Based Materials for Tissue Engineering Applications Biomacromolecules 2012, 13, 3678−3685
[5] Russell E. Lyons et al. Comparisons of Recombinant Resilin-like Proteins: Repetitive Domains Are Sufficient to Confer Resilin-like Properties Biomacromolecules 2009, 10, 3009–3014
[6] M. Kim et al. High yield expression of recombinant pro-resilin: Lactose-induced fermentation in E. coli and facile purification Protein Expression and Purification 52 (2007) 230–236
[7] Christopher M. Elvin et al. Synthesis and properties of crosslinked recombinant pro-resilin Vol 437|13 October 2005|doi:10.1038/nature04085