Bugg, Charles W. (2011) Domain organization of mutant Huntingtin fibrils. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:09192010-204534950
Huntington’s disease is a progressive, fatal neurodegenerative disorder caused by a polyglutamine (polyQ) expansion in exon 1 of the huntingtin gene (HDx1). A hallmark of the disease is the formation of fibrillar aggregates within cells. In vitro, HDx1 with a polyQ expansion forms fibrils that have a cross beta structure common to amyloid fibrils, but little else is definitively known about HDx1 fibril structure. We used electron paramagnetic resonance spectroscopy to study the organization of the major domains (N-terminus, polyQ, C-terminus) of HDx1 with 46Q within the fibril. Our data show that HDx1 fibrils do not have a parallel, in-register structure like most other disease-associated amyloid fibrils. The C-terminus is highly dynamic and is attached like a tail to the polyQ domain, which is mostly immobilized and forms the core of the fibril. However, the C-terminal portion of the polyQ lies outside the core and has a mobility similar to the C-terminus. The N-terminus produced heterogeneous spectra, indicating that it is able to sample multiple conformations. In sum, our study excluded the parallel, in-register arrangement of beta strands within HDx1 fibrils and represents a first step toward a high-resolution structure of HDx1 fibrils.
|Item Type:||Thesis (Dissertation (Ph.D.))|
|Subject Keywords:||Huntington's, huntingtin, amyloid, EPR, cross beta, polyglutamine, structure, electron paramagnetic resonance|
|Degree Grantor:||California Institute of Technology|
|Major Option:||Biochemistry and Molecular Biophysics|
|Thesis Availability:||Public (worldwide access)|
|Defense Date:||28 July 2010|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Charles Bugg|
|Deposited On:||01 Nov 2010 21:07|
|Last Modified:||26 Dec 2012 04:30|
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