THE TRANS-TRANSLATION INHIBITION IN MYCOBACTERIUM SMEGMATIS

Open Access
Author:
Chang, Hoon
Area of Honors:
Biochemistry and Molecular Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Kenneth Charles Keiler, Thesis Supervisor
  • Chen Pei David Tu, Honors Advisor
  • Scott Brian Selleck, Faculty Reader
Keywords:
  • Trans-translation
  • ClpXP
  • MIC
  • MBC
  • Fluorescent Reporter Assay
  • Mycobacterium Smegmatis
  • tmRNA
  • EF-Tu
Abstract:
Antibiotic resistance is a growing problem worldwide and has been spreading at an alarming rate over the past few decades. We are in dire need of new antimicrobial compounds that target novel pathways in bacteria. The focus of this project is the trans-translation pathway because it is required for growth and virulence in most pathogenic bacteria. More importantly, this ribosome-rescuing mechanism is only found in bacterial cells; therefore, pathogenesis can be prevented without harming eukaryotic cells. In order to investigate the inhibition of this pathway, series of experiments were performed on Mycobacterium smegmatis. M. smegmatis was chosen because it is non-pathogenic, grows quickly, and is a great model for M. tuberculosis. To identify potential antibiotics, a compound library at Novartis was screened for compounds that inhibited the trans-translation in E. coli. MIC and MBC assays were run on 27 of the screened molecules. Results showed that some of these molecules had bactericidal activities with very low MIC (≤ 10 μM). One of these compounds, E5, was tested using fluorescent reporter assays. The results suggested that E5 inhibits the trans-translation pathway by hindering proteolysis step of trans-translation. Currently, assays are being developed to identify a target of another inhibitor, F2.