This years Nobel prize in chemistry has been awarded to three researchers, Frances Arnold, George Smith and Gregory Winter for their work on enzyme research. Their work uses a technique called ‘directed evolution’ to create new enzymes. It does also tie in nicely with some of the subject material covered in the HL biochemistry option.
As I understand it, the work involves causing a gene (in a bacteria) to mutate randomly by using chemical mutagens or a technique called PCR. The mutation involves only one base pair being altered – this is called a point mutation.
A screening process will then take the best variant of the mutated gene and the process is repeated with the goal of evolving an enzyme that is needed for a particular role or has desired properties.
Obviously, this is a very simplified description of the process more information can be found here:
An advantage of using directed evolution is that it does not rely on an understanding of the protein structure, or the mechanism by which the protein works, whereas ‘traditional’ protein design does rely on this – something that is very difficult to predict / design or even understand.
Having to decide upon the quaternary structure of a protein must be enormously difficult and to do, even with today’s super computers. One would need to consider how the primary structure (order) of amino acids combine to form an alpha helix (the secondary structure) and then how this structure could bend and twist to form the tertiary structure through interactions between amino acids very far apart from each other in the primary structure. The task seems impossible, even before one starts it. Then you have to build it!
Of course, there are also some disadvantages to the technique such as there is no guarantee that the mutated gene will form a better enzyme. I imagine, many, many mutated enzymes are actually worse than the original as mother nature has had billions of years to evolve enzymes into the molecules that they are. Still, the potential is enormous.
Original article on directed evolution was sourced here:
Do you think that this sort of research is ethical? What happens if the process evolves an enzyme that is potentially harmful to humans? Do you think this sort of research should be allowed to be carried out? I’d love to hear your thoughts so please feel free to post them below.