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CHARACTERIZATION OF HEMERYTHRIN-LIKE PROTEIN RV2633C
Title
CHARACTERIZATION OF HEMERYTHRIN-LIKE PROTEIN RV2633C.
Creator
Cherne, Michelle D, Self, William, University of Central Florida
Abstract / Description
Hemerythrin-like protein Rv2633c is a small 18 kDa protein that is expressed in Mycobacterium tuberculosis (Mtb). Sequence analysis of Rv2633c predicts the presence of a hemerythrin-like domain, which binds dioxygen using a �-oxo-bridge (Fe-O-Fe), rather than a heme group. Though it is noticeably upregulated during macrophage infection and during in vitro acidification, the role of Rv2633c in Mtb survival has yet to be elucidated. This project aims to characterize the function of Rv2633c by...
Show moreHemerythrin-like protein Rv2633c is a small 18 kDa protein that is expressed in Mycobacterium tuberculosis (Mtb). Sequence analysis of Rv2633c predicts the presence of a hemerythrin-like domain, which binds dioxygen using a �-oxo-bridge (Fe-O-Fe), rather than a heme group. Though it is noticeably upregulated during macrophage infection and during in vitro acidification, the role of Rv2633c in Mtb survival has yet to be elucidated. This project aims to characterize the function of Rv2633c by studying the in vitro response of the recombinant protein to conditions present in the macrophage lysosome, such as reduced oxygen levels or the presence of reactive oxygen species. UV-visible spectroscopy is used to observe these changes, as the spectrum shows a characteristic peak at 330 nm that likely corresponds to the diiron cofactor in its native state. Our results show this spectrum shifts in response to hydrogen peroxide addition, showing the proposed environmental conditions can affect the active site. Bioinformatics techniques, such as the 3D modeling program SWISS-MODEL, have been used to hypothesize possible structure and function. Determining the function of Rv2633c may help explain how Mtb so readily evades the human immune system to reside in the macrophage.
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Date Issued
2016
Identifier
CFH2000011, ucf:45581
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH2000011
Biochemical Characterization of Rv2633c from Mycobacterium tuberculosis and the Effects of Mutagenesis on Iron Binding
Title
Biochemical Characterization of Rv2633c from Mycobacterium tuberculosis and the Effects of Mutagenesis on Iron Binding.
Creator
Strickland, Kyle, Self, William, Rohde, Kyle, Davidson, Victor, University of Central Florida
Abstract / Description
Mycobacterium tuberculosis (Mtb) is a pathogenic bacterium that is the causative agent of the disease Tuberculosis (TB). TB kills an estimated 1.8 million people annually and roughly one third of the world's population carries Mtb in a dormant state. Drug resistant Mtb strains are on the rise, thus a new method of combating this disease is paramount. Mtb survival inside of macrophages requires overcoming various stressors such as; iron restriction, reactive oxygen species, and hypoxic...
Show moreMycobacterium tuberculosis (Mtb) is a pathogenic bacterium that is the causative agent of the disease Tuberculosis (TB). TB kills an estimated 1.8 million people annually and roughly one third of the world's population carries Mtb in a dormant state. Drug resistant Mtb strains are on the rise, thus a new method of combating this disease is paramount. Mtb survival inside of macrophages requires overcoming various stressors such as; iron restriction, reactive oxygen species, and hypoxic conditions. Mtb employs the use of catalases, nitric oxide reductase, superoxide dismutase, and siderophores to aid in survival. These functions have also been found in a novel group of non-heme diiron binding proteins called hemerythrin-like proteins.The gene Rv2633c encodes a protein with the hemerythrin-like domain and has been shown to be upregulated under acidic or nutrient deficient conditions which coincides with Mtb infection of a macrophage. It has also been shown to be regulated by PhoP, Whib3, and DosR. In this work we expressed the wild type protein and several mutants heterologously in E. coli. The purified proteins were studied via UV-visible spectroscopic analysis, native polyacrylamide gel electrophoresis (native-PAGE) and analyzed for iron content.Our refined expression and purification protocol led to a significant increase in soluble protein with a di-iron cofactor. We found that mutagenesis of 11th amino acid, a histidine, led to the absence of the diiron co-factor. Reduction and autoxidation of protein was also achieved and characterized through UV-visible absorption. Native-PAGE gel analysis indicated only the dimeric form contained iron. This research is the first to produce large quantities of soluble iron laden protein, demonstrate that Rv2663c is capable of both reduction and autoxidation, and show it does not bind oxygen in a functional capacity. This information will enable future studies in protein crystallization, ligand interaction and in vivo studies.
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Date Issued
2019
Identifier
CFE0007729, ucf:52456
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007729