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Access Type

WSU Access

Date of Award

January 2011

Degree Type

Thesis

Degree Name

M.S.

Department

Biomedical Engineering

First Advisor

Dr. Timothy L. Stemmler

Second Advisor

Dr. Wei-ping Ren

Abstract

ABSTRACT

MOLECULAR DETAILS OF THE PROTEINS INVOLVED MITOCHONDRIAL IRON-SULFUR CLUSTER ASSEMBLY

by

YOGAPRIYA MURUGESAN

Oct 2011

Advisor: Prof. Timothy L. Stemmler

Major: Biomedical Engineering

Degree: Masters in Science

The neurodegenerative disease Friedrich's ataxia is caused by an inability to produce a functional mitochondrial protein `frataxin' which plays a major role in Fe-S cluster assembly. Physiopathological consequences due to frataxin deficiency causes disruption in the Fe-S cluster synthesis and mitochondrial iron overload leading to cell death resulting from the formation of reactive oxygen species. Iron-sulfur cofactors are vital to life and perform various essential functions throughout the cell ranging from electron transfer, enzyme catalysis and regulation of gene expression. Synthesis of Fe-S clusters is a multistep process that takes place predominately inside the mitochondrial by machinery that is directed by the scaffold protein Isu on which clusters are assembled. Iron present inside the mitochondrial membrane is believed to be delivered to the scaffold protein by means of frataxin during Fe-S cluster formation, whereas sulfide is provided to the assembly by means of cysteine desulfurase Nfs1. Alternatively, frataxin is also believed to act as a regulator for cysteine desulfurase activity. The transiently formed clusters are further transferred to the apoproteins by other set of proteins. Any defects in this pathway (from cluster formation to transfer) leads to several diseases such as Friedreich's ataxia, ISCU Myopathy, and Sideroblastic Anemia. Since current treatment strategies have suffered due to the lack of specific knowledge regarding the role of frataxin with its assembly protein partners, functional characterization of the protein at the molecular level would be essential in developing new strategies to treat this disorder. The focus of this project is to determine the molecular details of how the assembly proteins (frataxin, scaffold protein Isu, cysteine desulfurase Nfs1 interact with each other in vitro using orthologs of yeast and Drosophila in the presence and absence of the metal iron using various biophysical techniques.