The EF-P aminoacylation pathway may be a potential new target for antimicrobial drugs
MetadataShow full item record
Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Microbiology Honors Theses; 2013
Antibiotic resistance is a growing problem in both the developing world and industrialized nations. Bacterial infections are no longer cleared with a single round of antibiotics. The problem could be combated by discovering new pathways to target with drug treatment. One such possible pathway involves elongation factor P (EF-P), a bacterial protein involved in the regulation of antibiotic resistance and survival in other cellular stress. The modification of EF-P with (R)-β-Lysine by the lysyl-tRNA synthetase paralog PoxA affects protein synthesis in the ribosome by relieving stalling during translation of polyproline stretches (7). In PoxA deletion strains, EF-P is not modified decreasing cell replication rate, cell survival to stressful conditions and virulence of Salmonella enterica. By analyzing the contact surface between EF-P and PoxA and comparing it to the complex of a tRNA and an aminoacyl-tRNA synthetase, we were able to identify the novel interactions that could be a potential drug target. Most of the conserved interactions in the EF-P and PoxA complex correspond to the acceptor arm of the tRNA, but many of the contacts are unique. Through mutating amino acids involved in polar contacts between PoxA and EF-P and replacing them with alanine through site directed mutagenesis, it was determined which contacts (both novel and conserved) are important for EF-P recognition. This was measured by analyzing the aminoacylation kinetics using either EF-P or PoxA mutants. Our results suggest that recognition of EF-P by PoxA is mainly accomplished through binding of conserved amino acids that resemble the acceptor stem of a tRNA, but the arginine 235 contact may provide a target for antibiotic development.
Academic Major: Microbiology
Howard Hughes Medical Institute
Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.