
%0 Journal Article
%A Ali, Feda 
%A Thompson, Andrew J. 
%A Barrow, Colin J. 
%T The p3 Peptide, a Naturally Occurring Fragment of the Amyloid-&#946; Peptide (A&#946;)Found in Alzheimer's Disease, Has a Greater Aggregation Propensity <emph type="2">In Vitro</emph> Than Full-Length A&#946;, But Does Not Bind Cu<emph type="7">2+</emph>.
%J Australian Journal of Chemistry
%D 2000/07/21
%V 53
%N 4
%P 321-326
%K &#945;-Helix; &#946;-sheet; circular dichroism; copper binding; electrospray mass spectrometry; peptide synthesis.
%R https://doi.org/10.1071/CH99169
%U https://www.publish.csiro.au/paper/CH99169 
%X Cerebellar preamyloid from both Down&#8217;s syndrome and Alzheimer&#8217;s disease contains the p3 fragment (A&#946; 17&#8211;40/42) as a major amyloid-&#946; peptide (A&#946;) component. The p3 peptide was previously shown to form amyloid in vitro, but less readily than full-length A&#946;. Here we show that the p3 peptide has a greater &#946;-sheet-forming propensity than full-length A&#946;. Using circular dichroism spectroscopy we determined that in aqueous solutions the p3 peptide forms &#946;-sheet structure more readily than full-length A&#946;. The p3 peptide also has a lower &#945;-helical propensity than full-length A&#946; in the structure-forming solvent trifluoroethanol. These results indicate that the lower amyloidogenicity of the p3 peptide is not related to an inability to form &#946;-sheet structure. In this study we also show that, unlike full-length A&#946;, the p3 peptide does not bind Cu2+ ions. This inability to bind copper ions may explain why the p3 peptide appears to play a lesser role in Down&#8217;s syndrome and Alzheimer&#8217;s disease related neurodegeneration than does full-length A&#946;. 
