Neurotoxic, redox-competent Alzheimer's --amyloid is released from lipid membrane by methionine oxidation
Barnham, Kevin J., Ciccotosto, Giuseppe D., Tickler, Anna K., Ali, Feda E., Smith, Danielle G., Williamson, Nicholas A., Lam, Yuen-Han, Carrington, Darryl, Tew, Deborah, Kocak, Gulcan, Volitakis, Irene, Separovic, Frances, Barrow, Colin J., Wade, John D., Masters, Colin L., Cherny, Robert A., Curtain, Cyril C., Bush, Ashley I. and Cappai, Roberto 2003, Neurotoxic, redox-competent Alzheimer's --amyloid is released from lipid membrane by methionine oxidation, Journal of biological chemistry, vol. 278, no. 44, pp. 42959-42965.
Title
Neurotoxic, redox-competent Alzheimer's --amyloid is released from lipid membrane by methionine oxidation
American Society for Biochemistry and Molecular Biology, Inc.
Place of publication
Bethesda, Md.
Publication date
2003-10-31
ISSN
0021-9258 1083-351X
Summary
The amyloid β peptide is toxic to neurons, and it is believed that this toxicity plays a central role in the progression of Alzheimer's disease. The mechanism of this toxicity is contentious. Here we report that an Aβ peptide with the sulfur atom of Met-35 oxidized to a sulfoxide (Met(O)Aβ) is toxic to neuronal cells, and this toxicity is attenuated by the metal chelator clioquinol and completely rescued by catalase implicating the same toxicity mechanism as reduced Aβ. However, unlike the unoxidized peptide, Met(O)Aβ is unable to penetrate lipid membranes to form ion channel-like structures, and β-sheet formation is inhibited, phenomena that are central to some theories for Aβ toxicity. Our results show that, like the unoxidized peptide, Met(O)Aβ will coordinate Cu2+ and reduce the oxidation state of the metal and still produce H2O2. We hypothesize that Met(O)Aβ production contributes to the elevation of soluble Aβ seen in the brain in Alzheimer's disease.
Language
eng
Field of Research
060110 Receptors and Membrane Biology 110106 Medical Biochemistry: Proteins and Peptides (incl Medical Proteomics)