Faculty Advisor or Committee Member

José Argüello, Advisor

Identifier

etd-071613-221611

Abstract

"Mycobacterium tuberculosis causes tuberculosis, one of the most life-threatening diseases of all time. It infects the host macrophages and survives in its phagosome. The host phagosome is a very hostile environment where M. tuberculosis copes with high concentration of transition metals (Zn2+, Cu2+), low levels of others (Mn2+, Fe2+) and acidic pH. P-ATPases are membrane proteins that transport various ions against their electrochemical gradients utilizing the energy of ATP hydrolysis. Based on their primary sequences; seven of the twelve mycobacterial ATPases are classified as putative heavy metal transporters and a K+-ATPase, while the substrate of four (CtpE, CtpF, CtpH and CtpI) remains unknown. Consistent with their membrane topology and conserved amino acids, CtpE and CtpF are possibly P2 or P3-ATPases that transport alkali metals or protons. We examined the cellular roles of orthologous CtpE and CtpF in M. smegmatis, a non-pathogenic model organism. We hypothesized that these novel P- ATPases play an important role in transporting alkali metals and/or protons. We analyzed growth fitness of strains carrying mutations of the coding gens of these enzymes, in presence of various metals and different pHs, as well as the gene expression levels under different stress conditions. We observed that the M. smegmatis mutant strains, lacking of CtpF or CtpE, are sensitive to high concentrations (mM) of Mn2+. Furthermore, CtpE mutant is sensitive to alkali pH. Our results indicate that CtpE and CtpF might be an Mn2+ or H+-ATPase that are required for cell’s homeostasis sustainability."

Publisher

Worcester Polytechnic Institute

Degree Name

MS

Department

Chemistry & Biochemistry

Project Type

Thesis

Date Accepted

2013-07-16

Accessibility

Unrestricted

Subjects

Mycobacteria tuberculosis, P-type ATPases

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