Several human proteins are known to form amyloid fibrils, and these fibrils are associated with several devastating diseases, including Alzheimer's, Parkinson's, type II diabetes, and dialysis-related amyloidosis (DRA). One of these proteins, human beta-2- microglobulin (beta2m), can form amyloid fibrils in the presence of Cu(II). The fibrils formed by beta2m are the main pathogenic process underlying DRA. Like other amyloid systems, beta2m fibril formation proceeds by partial protein unfolding, subsequent oligomerization, and eventual elongation to form mature fibrils. While many general aspects of amyloid formation are understood, molecular-level information for the early stages of almost all amyloid forming reactions is only starting to emerge. This information, though, is critical for the rational development of therapeutics against amyloid diseases like DRA. We intend to obtain amino acid-level information about the unfolding and oligomerization of beta2m that precedes its fibril formation, with a particular emphasis on the unique role that Cu(II) plays in inducing this reaction. We will also investigate the molecular basis of several inhibitors that show promise for disrupting beta2m amyloid formation. To obtain the desired insight, we have three main aims. First, we will explore a combination of covalent labeling and hydrogen/deuterium exchange with mass spectrometric detection to obtain a detailed picture of the structural changes that betam and its oligomers undergo prior to amyloid formation. Second, we will develop and apply new labeling methods in conjunction with mass spectrometry to study metal-protein interactions with the goal of understanding the unique role that Cu(II) plays in beta2m amyloid formation. Third, our new labeling approaches will be applied to understand the molecular basis of three inhibitors of beta2m amyloid formation. Our prior work has revealed that Cu(II) destabilizes beta2m, allowing it to form oligomers prior to amyloid fibrils. We hypothesize that Cu(II) initiate the amyloid reaction by repositioning several regions of the protein and that Cu(II)'s coordination chemistry enables these structural and oligomeric changes in a way that is unique among transition metals. Our mass spectrometry-based methods will allow us to test this hypothesis, and along with the proposed inhibitor studies, we will obtain a deeper understanding of beta2m amyloid formation, which will facilitate the design of better therapeutics against DRA. Moreover, we expect that the techniques developed here will be applicable to other amyloid systems.

Public Health Relevance

The formation of protein amyloid fibrils is associated with about 20 human diseases, including Alzheimer's, Parkinson's, and Dialysis-Related Amyloidosis (DRA), but the molecular details of how these amyloids begin to form are mostly unknown. We intend to develop and apply new mass spectrometry based measurement tools that will provide the molecular details necessary to understand the amyloid formation of beta-2-microglobulin (beta2m), which is the protein implicated in DRA. The information that we uncover about beta2m should better inform efforts to design therapeutics against DRA but will also give insight into protein amyloid formation in general.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
4R01GM075092-12
Application #
9114580
Study Section
Enabling Bioanalytical and Imaging Technologies Study Section (EBIT)
Program Officer
Edmonds, Charles G
Project Start
2005-07-01
Project End
2017-07-31
Budget Start
2016-08-01
Budget End
2017-07-31
Support Year
12
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of Massachusetts Amherst
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
153926712
City
Amherst
State
MA
Country
United States
Zip Code
Limpikirati, Patanachai; Liu, Tianying; Vachet, Richard W (2018) Covalent labeling-mass spectrometry with non-specific reagents for studying protein structure and interactions. Methods 144:79-93
Liu, Tianying; Marcinko, Tyler M; Kiefer, Patrick A et al. (2017) Using Covalent Labeling and Mass Spectrometry To Study Protein Binding Sites of Amyloid Inhibiting Molecules. Anal Chem 89:11583-11591
Marcinko, Tyler M; Dong, Jia; LeBlanc, Raquel et al. (2017) Small molecule-mediated inhibition of ?-2-microglobulin-based amyloid fibril formation. J Biol Chem 292:10630-10638
Zhang, Zhe; Vachet, Richard W (2017) Gas-Phase Protein Salt Bridge Stabilities from Collisional Activation and Electron Transfer Dissociation. Int J Mass Spectrom 420:51-56
Borotto, Nicholas B; Zhang, Zhe; Dong, Jia et al. (2017) Increased ?-Sheet Dynamics and D-E Loop Repositioning Are Necessary for Cu(II)-Induced Amyloid Formation by ?-2-Microglobulin. Biochemistry 56:1095-1104
Zhang, Zhe; Vachet, Richard W (2015) Kinetics of Protein Complex Dissociation Studied by Hydrogen/Deuterium Exchange and Mass Spectrometry. Anal Chem 87:11777-83
Dong, Jia; Joseph, Crisjoe A; Borotto, Nicholas B et al. (2014) Unique effect of Cu(II) in the metal-induced amyloid formation of ?-2-microglobulin. Biochemistry 53:1263-74
Dong, Jia; Callahan, Katie L; Borotto, Nicholas B et al. (2014) Identifying Zn-bound histidine residues in metalloproteins using hydrogen-deuterium exchange mass spectrometry. Anal Chem 86:766-73
Borotto, Nicholas B; Degraan-Weber, Nicholas; Zhou, Yuping et al. (2014) Label scrambling during CID of covalently labeled peptide ions. J Am Soc Mass Spectrom 25:1739-46
Zhang, Zhe; Browne, Shaynah J; Vachet, Richard W (2014) Exploring salt bridge structures of gas-phase protein ions using multiple stages of electron transfer and collision induced dissociation. J Am Soc Mass Spectrom 25:604-13

Showing the most recent 10 out of 26 publications