Date of Award

2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Committee Chair

Tatyana Sysoeva

Committee Member

Luis R. Cruz-Vera

Committee Member

Ahmed Lawan

Research Advisor

Tatyana Sysoeva

Subject(s)

Drug resistance in microorganisms--Genetic aspects, Plasmids, Proteins, Escherichia coli, Urinary tract infections

Abstract

TraT is a multifunctional protein encoded by F-like plasmids that serves as a virulence factor in enteric bacteria. TraT protein confers benefits onto its cell, such as serum and macrophage resistance, resistance to bacteriophages, and the transfer of redundant plasmids through conjugation. Despite many roles and appearances in up to 80% of clinical antibiotic-resistant isolates of Escherichia coli, prior research has established little about TraT structure and how it relates to the protein’s many functions. This study aims to investigate the role of TraT in serum resistance by knocking out the traT gene via applying the CRISPR-Cas9 gene editing system. The study also aims to identify the possible involvement of amino acid residues of TraT that appear at the subunit interfaces in a structural model of this protein oligomer. This will be done by introducing mutations in these residues in the construct expressing recombinant TraT protein for in vitro analyses. The serum-killing assay demonstrated that TraT might not solely confer resistance to the serum complement, suggesting there might be other serum-resistance factors that work independently of TraT presence. Future work involves the structure analysis of altered TraT protein through X-ray crystallography, cryo-EM or size exclusion chromatography to analyze the oligomeric state of obtained in this thesis TraT variants.

Available for download on Wednesday, December 16, 2026

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