Let's take a step back in time
Equally as important as any advancements that had been made in the medical field, the protein purification field contributed arguably as much to saving wounded soldiers during the second world war. Before the Cohn process, soldiers who had lost a lot of blood would be bandaged up and the healing left to their weakened, fatigued and not to mention malnourished bodies. The Cohn process is a procedure that isolates albumin from other proteins. It uses the fact that human blood Albumin has an extremely low Isoelectric point when compared to other blood serum proteins to separate it from the rest of the serum. Thus through donor blood fractionation, albumin precipitate could be obtained. This allowed for relatively pure albumin transfusions to wounded soldiers which expedited their recovery (Albumin helps increase blood volume and clears the blood of certain toxins).
Ever since, scientists in the field have made large strides in their efforts of obtaining not only pure but large quantities of proteins not only for blood transfusions but for all aliments that involve the malfunction or absence of a proteins such as insulin deficiencies, hormone replacement therapies etc. Up until the 70s the need for pure protein had been evolving gradually and at the same pace with protein purification techniques, but at some point industries such as the food boomed and with them the need for proteins also exploded.
Organisms do not take well to their natural biochemical balances being perturbed
A lot of proteins being used today are being made in foreign organisms or animals and then being purified for our use. The problem is that these organisms are not used to making these proteins so they either 1. Do not want to produce these protein or 2. The production of the protein is harmful to its own well being. The worst case being that 1.is because of 2.
Let's say we decide on making a protein, an enzyme for example, that takes part in the citric acid cycle something like phosphoglucose isomerase. This sudden increase in PGI in the cytoplasma would radically decrease the amount of Glucose 6 phosphate, the problem with this being the organism might need this G6P for its essential functions. Thus, the more foreign PGI we make it produce the more we shorten the organisms lifespan. An organism that is being taken advantage of by many organisms is bacterium. We humans use bacteria to make our protein of interest, then we lyse the cells to collect. Phages, also take advantage of bacteria to replicate themselves and make the necessary proteins that they then pack into their capsids.
Pseudonucleus, phages solution to our problem
Bacteria obviously do not just let this happen. They have natural defenses to fight against all hijacking of their systems by phages. Phages have also developed weapons against these defences. And somewhere along the line, during this cat and mouse game that phages have been playing with bacteria, the phiKZ like phage 201 phi2-1 developed a trump card that its target Pseudomonas chlororaphis has not been able to figure out: The pseudonucleus.
Once the phage 201 phi2-1 infects pseudomonas chlororaphis, it surrounds its dna in a shell that is then grown to about a micrometer of diameter while being positioned to the center of the cell by phuZ like filaments. This compartement, which we call the "pseudonucleus" has being shown to functionally separate translation and transcription. Transcription being on the inside of the compartement means that the viral dna is protected from the bacterias endonucleases.
We are now trying to hijack the phages compartement so as to use it as a sort of micro bioreactor chambor. Since we know the phage has a way of bringing in proteins into the compartement once it is fully formed we would like to take advantage of that and send in the proteins that we make in the bacteria. This would mean avoiding the aforementioned problem of perturbing the natural biochemical balance of the bacteria too much. But first we have to be able to create the compartement, which is what our IGEM project will be about !
