Many debilitating human diseases are associated with the extracellular misfolding and aggregation of globular proteins to form fibrillar deposits that are rich in ?-sheet. There is considerable evidence that the process is initiated by local unfolding of the native structure to form aggregation-prone amyloidogenic intermediates. Aggregation then proceeds via nucleation-growth or downhill polymerization mechanisms. Despite their key role in amyloidogenesis, influencing the kinetic partitioning between aggregation and refolding pathways, very little is known about the structure of amyloidogenic intermediates because of their strong propensity to aggregate. The goals of the present proposal are to apply state-of-the-art NMR methods to elucidate the fundamental molecular events involved in initiation of transthyretin amyloidogenesis. Transthyretin amyloidosis is associated with numerous neurodegenerative diseases and cardiomyopathies. Misfolding and aggregation of transthyretin leads to fibrous deposits in the peripheral nerves and heart. Deposition of wild type protein is age related, whereas the familial diseases associated with genetic mutations that destabilize the quaternary and/or tertiary structure are early onset. This research will provide novel insights into the fundamental molecular mechanisms by which familial mutations destabilize the native transthyretin tetramer and initiate the aggregation cascade. Recently developed NMR relaxation dispersion experiments will be utilized to elucidate the structure of an aggregation-prone, early amyloidogenic intermediate and determine the kinetics and thermodynamics of the processes by which it is formed by partial unfolding of the monomeric transthyretin subunit.

Public Health Relevance

The proposed research will address the fundamental molecular mechanisms by which transthyretin misfolds and aggregates to cause human disease. Transthyretin amyloidosis plays a causative role in numerous age-related and familial neurodegenerative diseases and cardiomyopathies. This research will provide novel insights into the fundamental molecular mechanisms by which wild type transthyretin unfolds to form an aggregation-prone intermediate, and by which familial mutations destabilize the native transthyretin tetramer to initiate the aggregation cascade.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK034909-26
Application #
8642171
Study Section
Macromolecular Structure and Function B Study Section (MSFB)
Program Officer
Bishop, Terry Rogers
Project Start
1984-12-01
Project End
2018-03-31
Budget Start
2014-04-01
Budget End
2015-03-31
Support Year
26
Fiscal Year
2014
Total Cost
$412,163
Indirect Cost
$194,663
Name
Scripps Research Institute
Department
Type
DUNS #
781613492
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Aoto, Phillip C; Nishimura, Chiaki; Dyson, H Jane et al. (2014) Probing the non-native H helix translocation in apomyoglobin folding intermediates. Biochemistry 53:3767-80
Lim, Kwang Hun; Dyson, H Jane; Kelly, Jeffery W et al. (2013) Localized structural fluctuations promote amyloidogenic conformations in transthyretin. J Mol Biol 425:977-88
Nishimura, Chiaki; Dyson, H Jane; Wright, Peter E (2011) Consequences of stabilizing the natively disordered f helix for the folding pathway of apomyoglobin. J Mol Biol 411:248-63
Meinhold, Derrick W; Wright, Peter E (2011) Measurement of protein unfolding/refolding kinetics and structural characterization of hidden intermediates by NMR relaxation dispersion. Proc Natl Acad Sci U S A 108:9078-83
Nishimura, Chiaki; Dyson, H Jane; Wright, Peter E (2010) Energetic frustration of apomyoglobin folding: role of the B helix. J Mol Biol 396:1319-28
Wright, Peter E; Dyson, H Jane (2009) Linking folding and binding. Curr Opin Struct Biol 19:31-8
Felitsky, Daniel J; Lietzow, Michael A; Dyson, H Jane et al. (2008) Modeling transient collapsed states of an unfolded protein to provide insights into early folding events. Proc Natl Acad Sci U S A 105:6278-83
Schwarzinger, Stephan; Mohana-Borges, Ronaldo; Kroon, Gerard J A et al. (2008) Structural characterization of partially folded intermediates of apomyoglobin H64F. Protein Sci 17:313-21
Uzawa, Takanori; Nishimura, Chiaki; Akiyama, Shuji et al. (2008) Hierarchical folding mechanism of apomyoglobin revealed by ultra-fast H/D exchange coupled with 2D NMR. Proc Natl Acad Sci U S A 105:13859-64
Nishimura, Chiaki; Dyson, H Jane; Wright, Peter E (2008) The kinetic and equilibrium molten globule intermediates of apoleghemoglobin differ in structure. J Mol Biol 378:715-25

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