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Membrane charge dependent states of the beta-amyloid fragment Abeta (16-35) with differently charged micelle aggregates
- Source :
- Biochimica et biophysica acta. 1798(3)
- Publication Year :
- 2009
-
Abstract
- Abeta (16-35) is the hydrophobic central core of beta-amyloid peptide, the main component of plaques found in the brain tissue of Alzheimer's disease patients. Depending on the conditions present, beta-amyloid peptides undergo a conformational transition from random coil or alpha-helical monomers, to highly toxic beta-sheet oligomers and aggregate fibrils. The behavior of beta-amyloid peptide at plasma membrane level has been extensively investigated, and membrane charge has been proved to be a key factor modulating its conformational properties. In the present work we probed the conformational behavior of Abeta (16-35) in response to negative charge modifications of the micelle surface. CD and NMR conformational analyses were performed in negatively charged pure SDS micelles and in zwitterionic DPC micelles "doped" with small amounts of SDS. To analyze the tendency of Abeta (16-35) to interact with these micellar systems, we performed EPR experiments on three spin-labeled analogues of Abeta (16-35), bearing the methyl 3-(2,2,5,5-tetramethyl-1-oxypyrrolinyl) methanethiolsulfonate spin label at the N-terminus, in the middle of the sequence and at the C-terminus, respectively. Our conformational data show that, by varying the negative charge of the membrane, Abeta (16-35) undergoes a conformational transition from a soluble helical-kink-helical structure, to a U-turn shaped conformation that resembles protofibril models.
- Subjects :
- Circular dichroism
Amyloid peptide
spectroscopy
Magnetic Resonance Spectroscopy
Protein Conformation
Molecular Sequence Data
Static Electricity
Biophysics
Peptide
Micelle
Biochemistry
Protein structure
NMR spectroscopy
Static electricity
micelle
Organic chemistry
Computer Simulation
Amino Acid Sequence
Spin-labeled peptide
Spin label
Protein Structure, Quaternary
Micelles
chemistry.chemical_classification
Amyloid beta-Peptides
Circular Dichroism
Cell Membrane
Electron Spin Resonance Spectroscopy
amyloid
Cell Biology
Random coil
Peptide Fragments
Membrane
chemistry
Micelle solution
Indicators and Reagents
Spin Labels
EPR spectroscopy
Subjects
Details
- ISSN :
- 00063002
- Volume :
- 1798
- Issue :
- 3
- Database :
- OpenAIRE
- Journal :
- Biochimica et biophysica acta
- Accession number :
- edsair.doi.dedup.....946c75ba946732a741ae444b5736b01f