The 2018 Nobel Prize in Chemistry winners has been announced on October 3rd. One half of the prize was awarded to Frances H. Arnold “for the directed evolution of enzymes” and the other half jointly to George P. Smith and Sir Gregory P. Winter “for the phage display of peptides and antibodies”. According to the Royal Swedish Academy of Sciences, the winners “harnessed the power of evolution … and used it for purposes that bring the greatest benefit to mankind.” Interestingly enough, the experiments that won the scientists the prize actually closely resemble one of the earliest stages of life’s evolution: the evolution of proteins.

Protein is one of the most important molecules that makes life possible and is found in all known life forms. It is a type of macromolecules, meaning that it is a large molecule made out of subunits. The building blocks of protein are called amino acids. There are two main types of proteins: fibrous proteins and globular proteins. Fibrous proteins provide structural support to cells and tissues while globular proteins catalyze chemical reactions(enzymes) or act as signalling molecules(hormones).

The process of which cells make proteins by is called protein synthesis. The first step of protein synthesis is called transcription. It is where the cell copies the information encoded in the cell’s DNA onto a type of RNA called mRNA(messenger RNA). In the second step, called translation, the mRNA interacts with a molecule called rRNA(ribosomal RNA/ribosome) and according to the mRNA’s sequence, tRNA(transfer RNA) will bring the corresponding amino acids to the rRNA. The amino acids are joined together by peptide bonds to form amino acid chains called polypeptides. The polypeptides are then be folded and assembled together to form the complex protein structures. Protein synthesis is one of the most important biochemical processes in a cell and is sometimes referred to as the central dogma of molecular biology.

Like species, proteins also evolve over time. This is because random mutations in the cell’s DNA can lead to a slight change in the structure of the protein that can drastically change the behavior of the protein. Sometimes, one wrong amino acid is all it will take to deem a protein completely useless and other times, different polypeptide sequences can actually increase the protein’s efficiency at catalyzing chemical reaction or strength. Over time, evolution will rule out the mutations that are not favorable for survival because cells/organisms with mutations that increase protein function will have a much greater chance to have offsprings and pass down the gene. The result is the constant optimization protein function as generations go by.

However, the natural evolution of proteins is very slow because mutations are very rare. It takes hundreds or even thousands of generations to improve the function of one protein. Therefore, the three scientists thought to themselves: “can we come up with a way to simulate the evolution process of protein and speed it up manually?”. And this is exactly what they’ve achieved. For example, Dr. Arnold took DNA that corresponds to an enzyme and manually inserted many random mutations to it. Then, the DNA is inserted into bacteria, which will then make randomly mutated enzymes from the DNA. The different variations of the enzymes are then tested according to their efficiency of catalyzing chemical reactions. The same process is then repeated on the DNA of the enzymes that performed best in the test. By doing so multiple times, Dr. Arnold ended up with enzymes that are more than 250 times more efficient than the original. Her research can possibly bring a huge impact to the field of synthetic biology as enzymes are involved in the synthesis of numerous chemical and drugs and Improving the efficiency of enzymes can lead to higher yield and lower pollution processes.

An overview of Dr. Arnold’s experiment. (Image Source: The Royal Swedish Academy of Sciences)

This is one of the many examples of scientists being inspired by nature and really shows just how an amazing teacher evolution and nature is to us. Just remember, every time you look out the window at the beautiful biological world, 3.4 billion years worth of knowledge is out there waiting for us to explore and harness the power of.

Bibliography

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Fischman, Josh. “Revolution in Evolution Wins 2018 Nobel Prize in Chemistry.” Scientific American, 3 Oct. 2018, http://www.scientificamerican.com/article/revolution-in-evolution-wins-2018-nobel-prize-in-chemistry1/.

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Kyrpides, Nikos, et al. “Universal Protein Families and the Functional Content of the Last Universal Common Ancestor.” Journal of Molecular Evolution, vol. 49, no. 4, 1999, pp. 413–423., doi:10.1007/pl00006564.

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“The Nobel Prize in Chemistry 2018.” NobelPrize.org, http://www.nobelprize.org/prizes/chemistry/2018/press-release/.

“RNA and Protein Synthesis Review.” Khan Academy, Khan Academy, http://www.khanacademy.org/science/high-school-biology/hs-molecular-genetics/hs-rna-and-protein-synthesis/a/hs-rna-and-protein-synthesis-review.

“What Is Protein Synthesis.” Protein Synthesis, 27 Dec. 2015, http://www.proteinsynthesis.org/what-is-protein-synthesis/.