Difference between revisions of "Team:Queens Canada/Overview"
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| − | <p class="big"><font size="6" color="black"><p>Antifreeze proteins are a subset of ice-binding proteins. They adhere to the crystalline structure of ice by organizing ice-like water molecules on their surface. This makes further ice growth thermodynamically unfavourable. Although they vary greatly in structure, the ice-binding sites all have conserved properties. Here, we used the 37-residue, α-helical Type I AFP (we call it AFP8) from the winter flounder fish. We fused AFP8 directly to the C-terminus of CsgA. Most organisms that use AFPs circulate them in their blood as protection from freezing temperatures. However, AFPs can also be used to adhere to solid ice. In fact, the Arctic marine bacterium Marinomonas prymoriensis successfully uses an ice-binding domain as part of its large adhesin complex to keep itself at the top of the water column, where oxygen and nutrients are abundant [7]. | + | <p class="big"><font size="6" color="black"><p>Antifreeze proteins are a subset of ice-binding proteins. They adhere to the crystalline structure of ice by organizing ice-like water molecules on their surface. This makes further ice growth thermodynamically unfavourable. Although they vary greatly in structure, the ice-binding sites all have conserved properties. Here, we used the 37-residue, α-helical Type I AFP (we call it AFP8) from the winter flounder fish. We fused AFP8 directly to the C-terminus of CsgA. Most organisms that use AFPs circulate them in their blood as protection from freezing temperatures. However, AFPs can also be used to adhere to solid ice. In fact, the Arctic marine bacterium Marinomonas prymoriensis successfully uses an ice-binding domain as part of its large adhesin complex to keep itself at the top of the water column, where oxygen and nutrients are abundant [7].</p> |
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Revision as of 03:38, 30 October 2017
The Arctic is predicted to contain approximately 22% of the world’s oil and natural gas resources locked up beneath its basins. Due to the lack of natural resources in the surrounding tundra biome, bioremediation of oil spills can be especially challenging in the Arctic. As a result, an effective and environmentally safe method of petroleum cleanup may come in high demand during a major oil spill, which has been shown to incur costs ranging from the hundred millions to billions of dollars for conventional containment and cleanup.
The QGEM Team is turning to nature as our inspiration for building a safer and cheaper method of oil spill cleanup, using synthetic biology as our tool. This summer, we will be designing and engineering a bacterial biofilm-based material that functions to bind ice and recruit oil-degrading native marine bacteria. This will be done by engineering a protein naturally expressed in bacterial biofilm, CsgA, to append an ice-binding protein and a bacterial adhesin domain. The end product will be a dynamic, bifunctional biomaterial that may be deployed into the Arctic marine environment during oil spills as a bioremediation factory, with limited disturbance to the surrounding ecosystem
device (right) viewed under UV light. Looks like they work!
The Arctic is predicted to contain approximately 22% of the world’s oil and natural gas resources locked up beneath its basins. Due to the lack of natural resources in the surrounding tundra biome, bioremediation of oil spills can be especially challenging in the Arctic. As a result, an effective and environmentally safe method of petroleum cleanup may come in high demand during a major oil spill, which has been shown to incur costs ranging from the hundred millions to billions of dollars for conventional containment and cleanup. The QGEM Team is turning to nature as our inspiration for building a safer and cheaper method of oil spill cleanup, using synthetic biology as our tool. This summer, we will be designing and engineering a bacterial biofilm-based material that functions to bind ice and recruit oil-degrading native marine bacteria. This will be done by engineering a protein naturally expressed in bacterial biofilm, CsgA, to append an ice-binding protein and a bacterial adhesin domain. The end product will be a dynamic, bifunctional biomaterial that may be deployed into the Arctic marine environment during oil spills as a bioremediation factory, with limited disturbance to the surrounding ecosystem
Biofilms
In nature, the majority of bacteria exist as biofilms. Biofilms are organized bacterial communities that grow on an extracellular matrix scaffold composed mostly of polysaccharides, proteins and nucleic acids [2]. Biofilms typically carry negative connotations, particularly in medical settings where they are associated with antibiotic-resistant infections. However, we can exploit the same traits that make biofilms a formidable healthcare challenge to create engineered biomaterials. Bacteria in biofilms have several characteristic advantages over their planktonic (free-living) counterparts [2]:
Our engineered E. coli (expressing our CsgA fusions) can provide the oil-degrading M. hydrocarbonoclasticus with an ice-binding biofilm scaffold, significantly increasing its ability to survive and degrade hydrocarbons in harsh Arctic conditions.
CsgA Operon
CsgA is an amyloid protein monomer that polymerizes to form long nanofibres. Assembled CsgA nanofibres are referred to as curli. CsgA accounts for the majority of the proteinaceous component of E. coli biofilms. CsgA is secreted from the cells, and in wild-type E. coli it self-assembles to form curli nanofibres tethered to the cell surface by the nucleator protein CsgB. CsgA can also polymerize without CsgB in vitro. CsgA is relatively tolerant of C-terminal peptide fusions, granted they are less than about 40 amino acids in length. As an amyloid, CsgA is rich in β-sheet structure and remarkably resistant to denaturing conditions.
AFP8
Antifreeze proteins are a subset of ice-binding proteins. They adhere to the crystalline structure of ice by organizing ice-like water molecules on their surface. This makes further ice growth thermodynamically unfavourable. Although they vary greatly in structure, the ice-binding sites all have conserved properties. Here, we used the 37-residue, α-helical Type I AFP (we call it AFP8) from the winter flounder fish. We fused AFP8 directly to the C-terminus of CsgA. Most organisms that use AFPs circulate them in their blood as protection from freezing temperatures. However, AFPs can also be used to adhere to solid ice. In fact, the Arctic marine bacterium Marinomonas prymoriensis successfully uses an ice-binding domain as part of its large adhesin complex to keep itself at the top of the water column, where oxygen and nutrients are abundant [7].
References
- Kwok, R. 2010. Five hard truths for synthetic biology. Nature, 463, 288.
- Chalfie, M., Tu, Y., Euskirchen, G., Ward, W. W., Prasher, D. C. 1994. Green Fluorescent Protein as a Marker for Gene Expression. Science: 263(5148), 802-805.
