Unique Physicochemical Profile of β-Amyloid Peptide Variant Aβ1–40E22G Protofibrils: Conceivable Neuropathogen in Arctic Mutant Carriers
| ISSN: | 0022-2836 |
|---|---|
| DOI: | 10.1016/j.jmb.2004.03.028 |
| Přístupová URL adresa: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::55521e1487714e912809c703b7e8994c https://doi.org/10.1016/j.jmb.2004.03.028 |
| Rights: | CLOSED |
| Přírůstkové číslo: | edsair.doi.dedup.....55521e1487714e912809c703b7e8994c |
| Autor: | Lars Lannfelt, Astrid Gräslund, A Päiviö, Anita Westlind-Danielsson, Jüri Jarvet |
| Rok vydání: | 2004 |
| Předmět: |
Heterozygote
Circular dichroism Amyloid Stereochemistry Mutant Plaque Amyloid Peptide medicine.disease_cause Amyloid beta-Protein Precursor Alzheimer Disease Structural Biology mental disorders medicine Humans Molecular Biology chemistry.chemical_classification Mutation Amyloid beta-Peptides Molecular mass Circular Dichroism Point mutation Peptide Fragments Amino Acid Substitution chemistry Glycine Chromatography Gel |
| Zdroj: | Journal of Molecular Biology. 339:145-159 |
| ISSN: | 0022-2836 |
| DOI: | 10.1016/j.jmb.2004.03.028 |
| Popis: | A new early-onset form of Alzheimer's disease (AD) was described recently where a point mutation was discovered in codon 693 of the beta-amyloid (Abeta) precursor protein gene, the Arctic mutation. The mutation translates into a single amino acid substitution, glutamic acid-->glycine, in position 22 of the Abeta peptide. The mutation carriers have lower plasma levels of Abeta than normal, while in vitro studies show that Abeta1-40E22G protofibril formation is significantly enhanced. We have explored the nature of the Abeta1-40E22G peptide in more detail, in particular the protofibrils. Using size-exclusion chromatography (SEC) and circular dichroism spectroscopy (CD) kinetic and secondary structural characteristics were compared with other Abeta1-40 peptides and the Abeta12-28 fragment, all having single amino acid substitutions in position 22. We have found that Abeta1-40E22G protofibrils are a group of comparatively stabile beta-sheet-containing oligomers with a heterogeneous size distribution, ranging from >100 kDa to >3000 kDa. Small Abeta1-40E22G protofibrils are generated about 400 times faster than large ones. Salt promotes their formation, which significantly exceeds all the other peptides studied here, including the Dutch mutation Abeta1-40E22Q. Position 22 substitutions had significant effects on aggregation kinetics of Abeta1-40 and in Abeta12-28, although the qualitative aspects of the effects differed between the native peptide and the fragment, as no protofibrils were formed by the fragments. The rank order of protofibril formation of Abeta1-40 and its variants was the same as the rank order of the length of the nucleation/lag phase of the Abeta12-28 fragments, E22V>E22A?E22G>E22Q?E22, and correlated with the degree of hydrophobicity of the position 22 substituent. The molecular mass of peptide monomers and protofibrils were estimated better in SEC studies using linear rather than globular calibration standards. The characteristics of the Abeta1-40E22G suggest an important role for the peptide in the neuropathogenesis in the Arctic form of AD. |
| Databáze: | OpenAIRE |
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