The Relationship Between Structure and Function of the Heme-Scavenging Protein IsdX1

Persistent Link:
http://hdl.handle.net/10150/297658
Title:
The Relationship Between Structure and Function of the Heme-Scavenging Protein IsdX1
Author:
Kenrick, Anthony
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
In biological systems, iron is extremely important due to its use in electron transport, redox centers, oxygen transport, dismutation of reactive oxygen species, and structural stabilization. Among bacteria, iron is essential for healthy growth and many mechanisms exist for its acquisition. A prominent example is the iron-regulated surface determinant (Isd) system, which is found in many pathogens including the causative agent of anthrax, Bacillus anthracis. In the Isd system of B. anthracis, the protein IsdX1 is responsible for scavenging heme from host hemoglobin so that iron can be acquired through heme degradation. This process is not novel among bacteria that express Isd proteins, but IsdX1 is unique as the only example of an extracellular hemophore in Gram-positive bacteria. In order to understand the functional mechanics of IsdX1, it is necessary to characterize the protein with and without heme bound. This is accomplished by assessing proteolytic and thermal stability with limited proteolysis and circular dichroism. Using these tools, it is clear that IsdX1 is a stable protein in both the apo and holo forms that is quite resistant to proteolytic degradation. The binding of heme increases thermal stability to a moderate extent. These results suggest that IsdX1 is important for the growth of B. anthracis, and that heme binding influences the secondary structure content, possibly through a stabilizing conformational change.
Type:
text; Electronic Thesis
Degree Name:
B.S.
Degree Level:
bachelors
Degree Program:
Honors College; Biochemistry and Molecular Biophysics
Degree Grantor:
University of Arizona
Advisor:
McEvoy, Megan; Tsao, Tsu-Shuen

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleThe Relationship Between Structure and Function of the Heme-Scavenging Protein IsdX1en_US
dc.creatorKenrick, Anthonyen_US
dc.contributor.authorKenrick, Anthonyen_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractIn biological systems, iron is extremely important due to its use in electron transport, redox centers, oxygen transport, dismutation of reactive oxygen species, and structural stabilization. Among bacteria, iron is essential for healthy growth and many mechanisms exist for its acquisition. A prominent example is the iron-regulated surface determinant (Isd) system, which is found in many pathogens including the causative agent of anthrax, Bacillus anthracis. In the Isd system of B. anthracis, the protein IsdX1 is responsible for scavenging heme from host hemoglobin so that iron can be acquired through heme degradation. This process is not novel among bacteria that express Isd proteins, but IsdX1 is unique as the only example of an extracellular hemophore in Gram-positive bacteria. In order to understand the functional mechanics of IsdX1, it is necessary to characterize the protein with and without heme bound. This is accomplished by assessing proteolytic and thermal stability with limited proteolysis and circular dichroism. Using these tools, it is clear that IsdX1 is a stable protein in both the apo and holo forms that is quite resistant to proteolytic degradation. The binding of heme increases thermal stability to a moderate extent. These results suggest that IsdX1 is important for the growth of B. anthracis, and that heme binding influences the secondary structure content, possibly through a stabilizing conformational change.en_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
thesis.degree.nameB.S.en_US
thesis.degree.levelbachelorsen_US
thesis.degree.disciplineHonors Collegeen_US
thesis.degree.disciplineBiochemistry and Molecular Biophysicsen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorMcEvoy, Megan-
dc.contributor.advisorTsao, Tsu-Shuen-
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