Chiquita McCoy-Crisp
Kern Laboratory
Department of Biochemistry
Brandeis University
Illuminating Evolutionary Landscapes of Ancestral Enzymes Using a Custom Turbidostat
Poster Abstract
Directed evolution is a powerful method for creating biocatalysts for use in the synthesis of pharmaceuticals. Engineering enzymes with increased specificity and higher efficiency is commonly practiced, generally successful, and environmentally friendly, but this method is not without limitations as many projects have hit plateaus in kinetic improvement. To combat this issue, we are utilizing ancestral sequence reconstruction (ASR) followed by directed evolution to see if enzymes that have not undergone billions of years of selective pressures are easier to evolve than extant enzymes. As a model system, we have resurrected ancestors of E. Coli adenylate kinase (ADK), an essential enzyme that regulates the concentrations of ATP, ADP and AMP within cells. We are utilizing a custom turbidostat capable of sustaining eight separate cultures at a constant temperature and cell density to grow bacteria containing variants of ADK for long periods of time. High-throughput, next-generation sequencing is being used to monitor the mutational diversity that occurs within the ADK gene when these organisms are subjected to the selective pressure of low temperatures. If these ancestors are able to adapt faster, it would indicate that ASR followed by directed evolution has strong potential in the creation of biocatalysts for drug synthesis.
Personal Statement
My experience in the Kern lab has shown me the value and excitement of research. One of the most fundamental skills I have gained from doing research is perseverance and the ability to stay focused on the goal of scientific discovery. Even though the question my project set out to answer is fairly simple, actually answering it has proven to be incredibly complex. It required the construction of an intricate device, which was a project unto itself and required me to learn a variety of new skills such as soldering, coding, and laser cutting. This showed me that in order to achieve a goal, in science and otherwise, you sometimes have to first create the tools you need.
Working in a lab this summer also compelled me to hone my time management skills and my ability to balance multiple tasks at the same time. I have had to integrate planning experiments in advance with being flexible when unexpected roadblocks occur, as they do quite often. These capabilities have not only made me a more competent scientist but have also translated to many other facets of my life, making me a better critical thinker and problem solver. I am incredibly thankful to have had the opportunity to continue my research this summer, and I will carry the skills I have learned from this experience with me into my future career.