Mapping Interaction Through Compensatory PhoU Mutants in Escherichia Coli

Abstract

The purpose of this experiment was to identify the physical interaction site between two proteins in Escherichia Coli. These two proteins, PhoU and PhoR, are two proteins involved in Phosphate signal transduction. When these two proteins are mutated, so they no longer interact, the pathway is broken and signaling is inhibited. To break this pathway, we mutated one protein (PhoR) until we developed several mutations that no longer interact with PhoU. This loss of interaction is caused by a physical change to the site of interaction between the two proteins. We hypothesized that we could find a naturally occurring PhoU mutant that would compensate for the known PhoR mutation, thus restoring signaling. Through genetic sequencing of the PhoU mutant, we could then identify potential allele specific interaction sites between the two proteins allowing us to create a genetic map of the physical interaction site