Part:BBa_K4932002

Part description

This is a part that goes along with the LucKey in order to create a modular biosensor system. The idea is that you can swap out the small binding region on the LucCage in order to change what the system is targeting. This has been shown by the baker lab to work for recognising and providing a positive signal for COVID spike, troponin proteins (for detecting heart attacks), HER2 and more. This system was recently named in the literature by the baker lab (Alfredo Quijano-Rubio et al, 2021). The system is incredibly valuable for iGEM teams focussing on diagnostics because all you need to do is swap out the target region in order to target a new protein. HOW DOES THE BIOSENSOR WORK?[edit] There are two parts, the cage and the key. Both have a section of luciferase coded in to them. When the cage binds to the protein of interest, a change in conformation occurs which allows a ‘lever’ to open. This means the cage is in an open conformation and the key can bind. When the key binds, the luciferase is reconstituted and a positive signal is given.

Our input

We used this concept to create a diagnosing tool for E. coli. We decided to focus our project on a naturally occurring family of proteins, bacteriocins. Bacteriocins are produced by many types of bacteria and they bind to the same species in order to compete against them. They have co-evolved meaning they target extremely conserved regions. Specifically we used colicins. These are specific to E. coli and can be used to test for E. coli Note that we had to reverse the sequences because colicins are encoded in reverse. The sequence published here and on benching are NOT reversed. This is because the normal sequences are more useful.

Use for other teams

Other iGEM teams can add a protein of their choice to this system in order to create a very specific biosensor. They can either use a protein found in nature (easier) or they can design their own using machine learning methods (rosetta, alpha fold, protein MPNN, RF diffusion) If any iGEM team is interested in this please see our guide on exactly how to achieve this in our contributions page!

References: Quijano-Rubio, A., Yeh, HW., Park, J. et al. De novo design of modular and tunable protein biosensors. Nature 591, 482–487 (2021). https://doi.org/10.1038/s41586-021-03258-z