Type
Text
Type
Thesis
Advisor
Glynn, Steven E.
Date
2013-12-01
Keywords
circular dichroism, dimethylamine-borane complex, i-AAA, IPTG, m-AAA, MES | Biochemistry
Department
Department of Biochemistry and Cell Biology.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76929
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The ATP- dependent i-AAA protease pulls in and unwinds improperly folded and short-lived membrane proteins in order to maintain the integrity of the mitochondrial inner membrane. The i-AAA protease consists of an N-terminal domain, a single trans-membrane domain, a AAA ATPase domain and a metalloprotease domain. The role of the AAA domain is to unfold and translocate targeted proteins to protease domain where they are degraded. To further our understanding of the mechanism of this important enzyme, I sought to isolate and gain structural information on the individual domains of the i-AAA protease from the thermophilic eukaryote Myceliophthoya thermophile. I used sequence alignments to determine domain boundaries for the protease domain based on the structure of a related enzyme, FtsH. A construct containing this domain was cloned and expressed but did not express well enough on the large scale to move forward with crystallization. A construct containing the isolated N-terminal domain was expressed and purified in large quantities and used in crystallization trials. The high solubility of the protein prevented crystallization so I used reductive methylation to modify surface lysine residues and reduce solubility. Crystallization trials with this modified protein have yielded promising hits. Circular dichroism measurements indicated that the protein is largely alpha-helical in structure and chemical denaturation with urea suggested that the protein is stable with a mid-point of unfolding between 4 and 5 M urea. | 58 pages
Recommended Citation
Sheikh, Faiza, "Structural characterization of individual domains of an energy dependent mitochondrial protease" (2013). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2802.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2802