Publication Date
Summer 2024
Degree Type
Thesis
Degree Name
Master of Science (MS)
Department
Chemistry
Advisor
Laura Conrad; Ningkun Wang; Taylor Arhar
Abstract
Antibiotic resistance is a growing issue around the world, and the gram-negative bacterium Pseudomonas aeruginosa has been designated a high priority by both the World Health Organization and the Centers for Disease Control due to its propensity for causing nosocomial infections. One route of its resistance is through a modification that neutralizes the charge of lipid A within its outer membrane. The modified lipid avoids a favorable electrostatic interaction with cationic antimicrobial peptides such as colistin, preventing cell entry. This modification is produced via enzymes encoded by the arnBCADTEF pathway, in which the enzyme ArnA catalyzes two crucial steps. In order to characterize the enzymatic activity of ArnA we utilized Michaelis-Menten kinetics. As the N-terminal and C-terminal domains of ArnA have distinct roles in the pathway and have been shown to maintain function when separated, the C-terminal domain was first characterized on its own. The refined methods from this initial characterization were then utilized on the full-length enzyme to fully characterize it in its native state. We found that P. aeruginosa ArnA shows cooperative binding, and likely benefits from structural stabilization from the presence of both domains in its native form. We hypothesize that including the potential adjuvant in future experiments will show inhibition of ArnA. The development of adjuvant compounds that prevent the modification of lipid A will increase the efficacy of antibiotics such as colistin in multidrug resistant P. aeruginosa.
Recommended Citation
White, Keely N., "Kinetic Characterization of Pseudomonas aeruginosa ArnA" (2024). Master's Theses. 5583.
DOI: https://doi.org/10.31979/etd.8c7w-3w6s
https://scholarworks.sjsu.edu/etd_theses/5583
