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pubmed:abstractText |
Oligomers of 40- or 42-mer amyloid ?-protein (A?40, A?42) cause cognitive decline and synaptic dysfunction in Alzheimer's disease. We proposed the importance of a turn at Glu22 and Asp23 of A?42 to induce its neurotoxicity through the formation of radicals. Recently, a novel deletion mutant at Glu22 (E22?) of A?42 was reported to accelerate oligomerization and synaptotoxicity. To investigate this mechanism, the effects of the E22? mutation in A?42 and A?40 on the transformation of ?-sheets, radical production, and neurotoxicity were examined. Both mutants promoted ?-sheet transformation and the formation of radicals, while their neurotoxicity was negative. In contrast, E22P-A?42 with a turn at Glu22 and Asp23 exhibited potent neurotoxicity along with the ability to form radicals and potent synaptotoxicity. These data suggest that conformational change in E22?-A? is similar to that in E22P-A?42 but not the same, since E22?-A?42 exhibited no cytotoxicity, unlike E22P-A?42 and wild-type A?42.
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pubmed:affiliation |
Laboratory of Organic Chemistry in Life Science, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
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