Degree Type

Thesis

Date of Award

2019

Degree Name

Master of Science

Department

Biochemistry, Biophysics and Molecular Biology

Major

Microbiology

First Advisor

Thomas Bobik

Abstract

Bacterial microcompartments (MCPs) are subcellular organelles that are widespread among bacteria. MCPs consist of metabolic enzymes encapsulated within a protein shell and their function is to increase the efficiency of metabolic processes in part by sequestering toxic and volatile intermediates. MCPs are found in about 20% of bacteria. In several cases, MCP production is correlated to bacterial pathogenesis. In addition, because of their metabolic role in the human gut microbiome, MCPs are linked to cancer and heart disease. Only three of ten MCP types have been well-studied. Recently, a new type of MCP that is used to metabolize choline under anaerobic conditions and is linked to cardiovascular disease was discovered in Proteus and Desulfovibrio. The genes for the choline-utilizing (cut) MCP were also found in pathogenicity island II of uropathogenic Escherichia coli 536 through bioinformatics analyses. The main focus of this thesis is to describe biochemical and genetic studies carried out to increase our understanding of the E. coli 536 cut MCP. Our results show that E. coli 536 does indeed produce cut MCPs and that the cut genes are found in two adjacent operons containing three and thirteen genes, respectively. The main 13-gene cut operon contains genes responsible for anaerobic choline degradation and MCP formation, and the smaller cut operon contains three regulatory proteins that control transcription of the main cut operon. In addition, our studies show that the global regulatory systems, ArcAB, Fnr, and CRP (which are encoded outside the cut locus) all positively regulate transcription of the main cut operon. Overall, the findings reported here provide insights into the function and regulation of the cut MCP of E. coli 536. This further expands our understanding of bacterial MCPs and provides new knowledge that might be applied to their future use in nanotechnology and biomedicine.

Copyright Owner

Taylor Irene Herring

Language

en

File Format

application/pdf

File Size

81 pages

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