We have synthesized several potent inhibitors of beta-amyloid and other peptide fibrillogenesis containing N-methyl amino acids in alternate positions of sequences homologous to putative aggregation sites. Thus far, we have made inhibitors of beta-amyloid and prion peptide, and have recently synthesized a peptide designed to inhibit aggregation of huntingtin. The overall goal of this research is to understand the forces that promote the binding of these inhibitors to Alzheimer's beta-amyloid and related fibrils, in particular, the relative importance of hydrogen bonds involving the peptide backbone, and side chain interactions, including hydrophobic interactions and hydrogen bonds.
Specific aim 1 is to determine the modes of interaction between Abeta(1-40) and inhibitors of Abeta fibrillogenesis. We will determine the site of binding and orientation (parallel or antiparallel) between fibrillogenesis inhibitor peptides and Abeta(1-40) using solid state NMR spectroscopy, in particular, heteronuclear 15N-13C-REDOR pulse sequence NMR, with Dr. Robert Tycko of N.I.H. We will also study these peptide interactions and determine the structure of complexes between a fibrillogenesis inhibitor, Abeta(16-20)m and Abeta(1-40), using solution state NMR and other biophysical approaches.
Specific aim 2 is to understand the modes of association of inhibitor peptides with Abeta, and to understand the roles of hydrogen bonds, the hydrophobic effect, and conformational rigidity in these interactions.
Specific Aim 3 is to examine the role of amphiphilicity in determining the orientation, parallel or antiparallel of beta-sheet fibrils. We hope, with these to resolve a controversy in the Abeta literature. We hypothesize that whereas non-amphiphilic peptides tend to form fibrils with antiparallel beta-sheets, amphiphilic peptides such as Abeta(1-40) are driven towards forming fibrils with parallel beta-sheets. This hypothesis will be tested using REDOR and other biophysical techniques on short Abeta peptides known to form antiparallel beta-sheet fibrils. We will test the hypothesis that the addition of fatty acids to render these peptides amphiphilic will reverse their orientation to parallel beta-sheets.
Specific aim 4 is to examine the ability of a peptide backbone and side chain methylated polyglutaminyl peptide to inhibit aggregation and disaggregate fibrils of huntingtin, and to examine their mode of interaction with huntingtin peptides in vitro and in vivo. These inhibitor designs may be useful for understanding the forces that promote fibrillogenesis in neuro-degenerative diseases, and in designing novel diagnostic or therapeutic agents for these diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS042852-01A1
Application #
6572736
Study Section
Biophysical Chemistry Study Section (BBCB)
Program Officer
Murphy, Diane
Project Start
2003-01-15
Project End
2007-12-31
Budget Start
2003-01-15
Budget End
2003-12-31
Support Year
1
Fiscal Year
2003
Total Cost
$383,428
Indirect Cost
Name
University of Chicago
Department
Pathology
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
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Lu, Jun-Xia; Qiang, Wei; Yau, Wai-Ming et al. (2013) Molecular structure of ?-amyloid fibrils in Alzheimer's disease brain tissue. Cell 154:1257-68
Cloe, Adam L; Orgel, Joseph P R O; Sachleben, Joseph R et al. (2011) The Japanese mutant A? (?E22-A?(1-39)) forms fibrils instantaneously, with low-thioflavin T fluorescence: seeding of wild-type A?(1-40) into atypical fibrils by ?E22-A?(1-39). Biochemistry 50:2026-39
Bockhorn, Jessica J; Lazar, Kristi L; Gasser, Adam J et al. (2010) Novel semisynthetic method for generating full length beta-amyloid peptides. Biopolymers 94:511-20
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Darnell, Gregory D; Derryberry, JohnMark; Kurutz, Josh W et al. (2009) Mechanism of cis-inhibition of polyQ fibrillation by polyP: PPII oligomers and the hydrophobic effect. Biophys J 97:2295-305
Chopra, Neeraj; Gan, Wenxun; Schreiber, Hans et al. (2009) Versatile cyclic templates for assembly of axially oriented ligands. Bioconjug Chem 20:231-40
Paravastu, Anant K; Qahwash, Isam; Leapman, Richard D et al. (2009) Seeded growth of beta-amyloid fibrils from Alzheimer's brain-derived fibrils produces a distinct fibril structure. Proc Natl Acad Sci U S A 106:7443-8
Tycko, Robert; Sciarretta, Kimberly L; Orgel, Joseph P R O et al. (2009) Evidence for novel beta-sheet structures in Iowa mutant beta-amyloid fibrils. Biochemistry 48:6072-84
Carnemolla, Ronald; Ren, Xuefeng; Biswas, Tapan K et al. (2008) The specific amino acid sequence between helices 7 and 8 influences the binding specificity of human apolipoprotein A-I for high density lipoprotein (HDL) subclasses: a potential for HDL preferential generation. J Biol Chem 283:15779-88

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