Protein Evolution using Antibiotic Resistance as a System.

Ernesto Arcia, Dhanya Dhananjayan, Dimitra Keramisanou, Ioannis Gelis

University of South Florida

Evolution of antibiotic resistance has become a big problem when trying to deal with bacteria that pose a threat to human health. In this project we examine the intermolecular epistatic effect between multiple E. Coli genes and a set of intermediates along the evolutionary pathway of antibiotic deactivating enzymes. A set of engineered E. coli cell lines were exposed to increasing antibiotic concentrations to determine the minimal inhibitory concentration (MIC), in order to use it as a fitness proxy. A total of 110 experiments were performed in duplicate, comprised of a combination of 22 strains and five evolutionary intermediates of the deactivating enzymes. The results show that the MIC of some of the strains have a statistically significant difference when compared to the wild type while others do not, suggesting that some genes have a bigger impact in facilitating evolution and survival compared to others.