Copper and Zinc Binding Modulates the Aggregation and Neurotoxic Properties of the Prion Peptide PrP106-126
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- 作者：Michael F. Jobling ; Xudong Huang ; Leanne R. Stewart ; Kevin J. Barnham ; Cyril Curtain ; Irene Volitakis ; Matthew Perugini ; Anthony R. White ; Robert A. Cherny ; Colin L. Masters ; Colin J. Barrow ; Steven J
- 刊名：Biochemistry
- 出版年：2001
- 出版时间：July 10, 2001
- 年：2001
- 卷：40
- 期：27
- 页码：8073 - 8084
- 全文大小：186K
- 年卷期：v.40,no.27(July 10, 2001)
- ISSN：1520-4995
文摘
The abnormal form of the prion protein (PrP) is believed to be responsible for the transmissiblespongiform 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
peptide (A) also undergoes fibrillogenesis to become neurotoxic. A aggregation and toxicity is highlysensitive 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 hadreduced Cu2+ and Zn2+ levels approximately 3-fold. Restoring Cu2+ and Zn2+ to their original levelsrestored aggregation. Circular dichroism showed that the Chelex-100 treatment reduced the aggregated-sheet content of the peptide. Electron paramagnetic resonance spectroscopy identified a 2N1S1Ocoordination to the Cu2+ atom, suggesting histidine 111 and methionine 109 or 112 are involved. Nuclearmagnetic resonance confirmed Cu2+ and Zn2+ binding to His-111 and weaker binding to Met-112. AnN-terminally acetylated PrP106-126 peptide did not bind Cu2+, implicating the free amino group inmetal binding. Mutagenesis of either His-111, Met-109, or Met-112 abolished PrP106-126 neurotoxicityand its ability to form fibrils. Therefore, Cu2+ and/or Zn2+ binding is critical for PrP106-126 aggregationand neurotoxicity.
peptide (A) also undergoes fibrillogenesis to become neurotoxic. A aggregation and toxicity is highlysensitive 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 hadreduced Cu2+ and Zn2+ levels approximately 3-fold. Restoring Cu2+ and Zn2+ to their original levelsrestored aggregation. Circular dichroism showed that the Chelex-100 treatment reduced the aggregated-sheet content of the peptide. Electron paramagnetic resonance spectroscopy identified a 2N1S1Ocoordination to the Cu2+ atom, suggesting histidine 111 and methionine 109 or 112 are involved. Nuclearmagnetic resonance confirmed Cu2+ and Zn2+ binding to His-111 and weaker binding to Met-112. AnN-terminally acetylated PrP106-126 peptide did not bind Cu2+, implicating the free amino group inmetal binding. Mutagenesis of either His-111, Met-109, or Met-112 abolished PrP106-126 neurotoxicityand its ability to form fibrils. Therefore, Cu2+ and/or Zn2+ binding is critical for PrP106-126 aggregationand neurotoxicity.