Ready, Set, Synthesize Protein!

So far this summer I have participated in Dress-Up Mondays (this Monday was rather formal!), liquid nitrogen ice cream, lab meetings, lab dates and excursions to lunch and ice cream (again because we just cannot get enough), karaoke in lab as we work, and other shenanigans.  But this blog is supposed to be on the research that I am doing? Very well, I can discuss that too!

The basic premise of my research is using unnatural amino acids (aka variations of the original 20 amino acids that compose protein) to give novel biochemical characteristics to protein. This is a very general topic. Currently I have about six different projects that are all based off of this general theme.  The past two weeks have been a lot of protein expression and purification, and gel electrophoresis. The process of making protein is rather simple. While it is possible to string together a peptide through attaching amino acids like beads on a string, this is practically impossible to do for large proteins (greater than 40-50 amino acids). The method that we use incorporates the bacterial world, namely our friend E. coli. To do this, we first transform the E. coli to give them the ability to make our protein of interest with a mutation that allows the insertion of the unnatural amino acid. Then we “induce” the cells to just keep pumping out the protein that we want (like little cell factories!) to which we have added our unnatural amino acid.

Once we have the protein (with its incorporated unnatural amino acid) we can then do several reactions with it. The main one that we perform is called a “click” reaction. In this reaction an azide and an alkyne (two chemical functional groups) latch together (in which one of these groups is in the protein). This coupling is not hydrolysable and is thus very stable. This is really exciting as this can be used for techniques such as enzyme immobilization and drug delivery. Other unnatural amino acids allow us to modulate the activity of the enzyme.

Despite the exciting goals of these projects, so far we have not found much success. We believe that we do not have the conditions required to properly produce these proteins, and that we might be adding two much of the unnatural amino acids which in turn kills the cells before they can make enough protein for us. However, most of our results are promising and I look forward to what the next results will be!