2023 50 B2

Structure Function Studies of Pseudomonas aeruginosa Protein PA2271

By: Patricia Faye Uychoco

Department: Chemistry & Biochemistry

Faculty Advisor: Dr. Misty Kuhn

Polyamines are polycationic organic molecules that have many important roles in bacterial cell function, such as gene expression, DNA and RNA synthesis, stress resistance and biofilm regulation. In some bacteria, increasing concentrations of spermidine can cause cellular toxicity which needs to be regulated through acetylation using polyamine acetyltransferases. A common protein responsible for this regulation in various bacterial species is the spermidine/spermine N-acetyl-transferase SpeG, however other polyamine acetyltransferases exist. No speG gene has been found in Pseudomonas aeruginosa, so regulation of polyamines in this bacterium is not yet understood. Therefore, we are interested in whether an unidentified acetyltransferase can fulfill this role of acetylating polyamines in this organism. During a broad-substrate screening assay, we previously identified a candidate protein called PA2271 that acetylated spermine and spermidine at low levels. To determine the substrate specificity and kinetically characterize the PA2271 enzyme further we have designed a polyamine substrate screening assay and docked polyamine molecules into the crystal structure of the protein. In this study we will propose a binding mode for polyamines to determine the critical residues that are involved in catalysis.