The intact human acetylcholinesterase C-terminal oligomerization domain is alpha-helical in situ and in isolation, but a shorter fragment forms beta-sheet-rich amyloid fibrils and protofibrillar oligomers.

Cottingham, MG; Voskuil, J; Vaux, D

Journal article

The intact human acetylcholinesterase C-terminal oligomerization domain is alpha-helical in situ and in isolation, but a shorter fragment forms beta-sheet-rich amyloid fibrils and protofibrillar oligomers.

Abstract:: A 14-residue fragment of the C-terminal oligomerization domain, or T-peptide, of human acetylcholinesterase (AChE) shares sequence homology with the amyloid-beta peptide implicated in Alzheimer's disease and can spontaneously self-assemble into classical amyloid fibrils under physiological conditions [Greenfield, S. A., and Vaux, D. J. (2002) Neuroscience 113, 485-492; Cottingham, M. G., Hollinshead, M. S., and Vaux, D. J. (2002) Biochemistry 41, 13539-13547]. Here we demonstrate that the conformation of this AChE(586-599) peptide, both before and after fibril formation, is different from that of a longer peptide, T(40), corresponding to the entire 40-amino acid T-peptide (residues 575-614 of AChE). This peptide is prone to homomeric hydrophobic interactions, consistent with its role in AChE subunit assembly, and possesses an alpha-helical structure which protects against the development of the beta-sheet-rich amyloidogenic conformation favored by the shorter constituent AChE(586-599) fragment. Using a conformation-sensitive monoclonal antibody raised against the alpha-helical T(40) peptide, we demonstrate that the conformation of the T-peptide domain within intact AChE is antigenically indistinguishable from that of the synthetic T(40) peptide. A second monoclonal antibody raised against the fibrillogenic AChE(586-599) fragment recognizes not only beta-sheet amyloid aggregates but also SDS-resistant protofibrillar oligomers. A single-antibody sandwich ELISA confirms that such oligomers exist at micromolar peptide concentrations, well below that required for formation of classical amyloid fibrils. Epitope mapping with this monoclonal antibody identifies a region near the N-terminus of the peptide that remains accessible in oligomer and fibril alike, suggesting a model for the arrangement of subunits within AChE(586-599) protofibrils and fibrils.

Publication status:: Published

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APA Style

Cottingham, M. G., Voskuil, J., & Vaux, D. (2003). The intact human acetylcholinesterase C-terminal oligomerization domain is alpha-helical in situ and in isolation, but a shorter fragment forms beta-sheet-rich amyloid fibrils and protofibrillar oligomers. Biochemistry, 42(36), 10863–10873.

MLA Style

Cottingham, M. G., et al. “The Intact Human Acetylcholinesterase C-Terminal Oligomerization Domain Is Alpha-Helical in Situ and in Isolation, but a Shorter Fragment Forms Beta-Sheet-Rich Amyloid Fibrils and Protofibrillar Oligomers.” Biochemistry, vol. 42, no. 36, 2003, pp. 10863–73.

Chicago Style

Cottingham, MG, J Voskuil, and D Vaux. 2003. “The Intact Human Acetylcholinesterase C-Terminal Oligomerization Domain Is Alpha-Helical in Situ and in Isolation, but a Shorter Fragment Forms Beta-Sheet-Rich Amyloid Fibrils and Protofibrillar Oligomers.” Biochemistry 42 (36): 10863–73.
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