nathaliaraquelx
commented
3 years ago Transcription – Independent Protein – Based Biosensors
DOI: 10.3390/genes9080375
- Integrated TIPB
Receptor domain/s for a target ligand are expressed as a fusion protein with little to no linker domain to a response domain. Most closely mimics natural enzymes/signaling proteins. Advantages – can generate very selective activity with large linear and dynamic ranges. One of the limitations is the background knowledge since most integrated TIPBs are made using known protein domains. Additionally, design process is not trivial and rather complicated. One of biggest limitations is that integrated TIPBs are designed in a finite solution space, meaning that chances of success rely on very specific circumstances.
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Semi modular TIPB
Involve using linkers to coordinate receptor and response domain activity in response to the target ligand. Advantages: higher degree of engineering possibilities than fully integrated designs. Limitations: optimal linker length/composition is difficult to know a priori. Additionally, often many different linker configurations need to be tested before an optimal sensor is generated. Design choices of linker require a moderate degree of specialized skill.
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Modular TIPB
Use protein tethers for receptor domain induced co-localization of response domains. Tethers do not use conformational changes to induce response but allow the recruitment of all necessary signaling components into one location. Construction is simpler than semi – modular TIPB or integrated TIPB. Also, there is fewer constraints when building a design. Limitations for the design strategy include baseline activation and choice of response. Since the only barrier to activation is co-localization, stochastic movement of sensor components is more likely to influence biosensor output and thus there might be more noise and decreased sensitivity.
A colleague from the lab made this little sum up of modular transcription based biosensors. It is definitely worth reading and maybe even creating our own version in Portuguese? Why not...
Transcription Factor - Based biosensors (TFB)
DOI: 10.3390/genes9080375
>Modular Transcription Factor – Based Biosensors: involves the use of modular protein domains to induce transcription in response to target ligand. The critical components in this type of biosensor construction are protein domains that dimerize/co-ordinate with each other in the presence of a target ligand.Limitations:
Finding/creating ligand binding domains that either dimerize or produce useful conformational change upon ligand association can be more difficult -> more complicated protein engineering.
To enhance this technique would require that binding proteins/peptides be generated using random selection techniques such as phage/yeast display or two hybrid system.