Difference between revisions of "Part:BBa K1921014"

Latest revision as of 07:13, 20 October 2016

PETase+INPN

Sequence and Features

Usage

This part is a fusion protein of the N-terminal of ice nucleation protein and PETase. PETase is a new protein enzyme found in bacteria which can decompose PET. Through this method, we can anchor PETase on the out membrane of Escherichia coli, then we can use this typical Escherichia coli to decompose PET. This is a way called whole cell catalysis. Using this method, we don’t need to purify the protein. In addition, prokaryote surface display system method is mature enough. INP is frequently used to develop whole-cell biocatalysts, primarily because: (i) INP does not appear to be hampered by the size of the passenger; and (ii) INP is compatible with the translocation and surface display of proteins that contain multiple cofactors as well as disulfide-bond-containing passengers.

Biology

PETase was found from a kind of microorganism(Ideonella sakaiensis 201-F6) living on PET as the main carbon source. It can degrade macromolecular polymers into monomers. PETase is the only enzyme found in bacteria which can degrade PET.
Surface expression of recombinant proteins was first described more than 30 years ago.Bacterial surface display entails the presentation of recombinant proteins or peptides on the surface of bacterial cells. Escherichia coli is the most frequently used bacterial host for surface display and, as such, a variety of E. coli display systems have been described that primarily promote the surface exposure of peptides and small proteins. INP is an OMP that is found in several plant pathogenic bacteria. Our inaK is from Pseudomonas. INP has several unique structural and functional features that make it highly suitable for use in a bacterial surface display system. The specific amino acids of the N-terminal domain are relatively hydrophobic and link the protein to the OM via a glycosylphosphatidylinositol anchor. The C-terminal domain of the protein is highly hydrophilic and exposed to the medium. The central part of INP comprises a series of repeating domains that act as templates for ice crystal formation. However, the N-terminal domain appears to be the only prerequisite for successful targeting and surface-anchoring.

Reference

[1] Shosuke, Yoshida, 1, 2*, Kazumi, Hiraga, 1, Toshihiko, Takehana, 3, Ikuo, Taniguchi, 4, Hironao, Yamaji, 1, Yasuhito, Maeda, 5, Kiyotsuna, Toyohara, 5, Kenji, Miyamoto, 2†, Yoshiharu, Kimura, 4, Kohei, Oda1. A bacterium that degrades and assimilates poly(ethylene terephthalate)[J]. SCIENCE, 2016: 1196-1199
[2]Edwin, van, Bloois1, Remko, T, Winter1, Harald, Kolmar2, and, Marco, W, Fraaije. Decorating microbes: surface display of proteins on Escherichia coli[J]. CELL Press, 2011, 29(2): 79-86

Pre-expression

Figure 1.This is the pre-expression using E.coli BL21 at 37 ℃.

Figure 2. This is the pre-expression using E.coli BL21 at 16 ℃.

Figure 3. This is the pre-expression using E.coli BL21 at 25 ℃.

Figure 4.This is the pre-expression using E.coli BL21 induced by different concentration of IPTG.

Figure 5.This is the pre-expression using E.coli BL21 induced by different concentration of IPTG.

Figure 6.This is the pre-expression using E.coli BL21 induced 24h by different concentration of IPTG at 16℃ and 25℃.

Surface display HPLC results

Figure 7. Relative enzyme activity of engineering bacteria E.coli(BL21)/pET22b(+)NP when induced at 16℃.

Figure 8.Relative enzyme activity of engineering bacteria E.coli(BL21)/pET22b(+)NP when induced at 25℃ with different amount of bacteria.

Figure 9. Relative enzyme activity of engineering bacteria E.coli(BL21)/pET22b(+)NP when induced with 0.1mM IPTG for 24h.

Figure 10.Relative enzyme activity of engineering bacteria E.coli(BL21)/pET22b(+)NP when induced at 16℃ with 0.1mM IPTG for 1h, 4h, 8h, 12h, 16h and 20h.