Abstract

Phosphate is an essential nutrient for all forms of life. Escherichia coli has a PhoR/PhoB two component regulatory system that controls the expression of various genes whose products allow the cell to thrive in low phosphate environments. The signaling mechanism of the PhoR/PhoB system has been studied and the phosphorylation cascade that controls gene expression is well understood. What is still unknown is how PhoR senses the phosphate level of the environment. The PstS, PstC, PstA, PstB, and PhoU proteins play a role in this signal sensing. This work confirms the hypothesis that the PstSCAB complex senses the environmental phosphate and that phosphate signal is passed through PhoU to PhoR. Further, this work characterizes residues important for interaction on PhoU and PhoR and identifies a structural model for interaction. This model points to a potential mechanism for PhoU mediated signaling to PhoR. We tested this model with direct coupling analysis and obtained further confirmation. Further use of these techniques may elucidate more of the interactions necessary for proper phosphate signaling.

Degree

PhD

College and Department

Life Sciences; Microbiology and Molecular Biology

Rights

http://lib.byu.edu/about/copyright/

Date Submitted

2014-12-01

Document Type

Dissertation

Handle

http://hdl.lib.byu.edu/1877/etd7359

Keywords

PhoR, PhoU, PstSCAB, Pho regulon, two component signal transduction, PAS domain, direct coupling analysis, protein structure modeling

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