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Copper and zinc binding modulates the aggregation and neurotoxic properties of the prion peptide PrP106-126
journal contribution
posted on 2001-07-10, 00:00 authored by M F Jobling, X Huang, L R Stewart, K J Barnham, C Curtain, I Volitakis, M Perugini, A R White, R A Cherny, C L Masters, Colin BarrowColin Barrow, S J Collins, A I Bush, R CappaiThe abnormal form of the prion protein (PrP) is believed to be responsible for the transmissible spongiform encephalopathies. A peptide encompassing residues 106-126 of human PrP (PrP106-126) is neurotoxic in vitro due its adoption of an amyloidogenic fibril structure. The Alzheimer's disease amyloid beta peptide (Abeta) also undergoes fibrillogenesis to become neurotoxic. Abeta aggregation and toxicity is highly sensitive to copper, zinc, or iron ions. We show that PrP106-126 aggregation, as assessed by turbidometry, is abolished in Chelex-100-treated buffer. ICP-MS analysis showed that the Chelex-100 treatment had reduced Cu(2+) and Zn(2+) levels approximately 3-fold. Restoring Cu(2+) and Zn(2+) to their original levels restored aggregation. Circular dichroism showed that the Chelex-100 treatment reduced the aggregated beta-sheet content of the peptide. Electron paramagnetic resonance spectroscopy identified a 2N1S1O coordination to the Cu(2+) atom, suggesting histidine 111 and methionine 109 or 112 are involved. Nuclear magnetic resonance confirmed Cu(2+) and Zn(2+) binding to His-111 and weaker binding to Met-112. An N-terminally acetylated PrP106-126 peptide did not bind Cu(2+), implicating the free amino group in metal binding. Mutagenesis of either His-111, Met-109, or Met-112 abolished PrP106-126 neurotoxicity and its ability to form fibrils. Therefore, Cu(2+) and/or Zn(2+) binding is critical for PrP106-126 aggregation and neurotoxicity.
History
Journal
BiochemistryVolume
40Issue
27Pagination
8073 - 8084Publisher
American Chemical SocietyLocation
Washington, D.C.Publisher DOI
ISSN
0006-2960Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2001, American Chemical SocietyUsage metrics
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No categories selectedKeywords
Amino Acid SequenceAnimalsBinding SitesCation Exchange ResinsCells, CulturedCerebellumChelating AgentsChromatography, High Pressure LiquidCircular DichroismCopperElectron Spin Resonance SpectroscopyHistidineHumansMass SpectrometryMethionineMiceMice, KnockoutMolecular Sequence DataMutagenesis, Site-DirectedNephelometry and TurbidimetryNeuronsNuclear Magnetic Resonance, BiomolecularPeptide FragmentsPrionsProtein Structure, SecondaryResins, SyntheticUltracentrifugationZinc
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