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Engineered non-fluo...
Engineered non-fluorescent Affibody molecules facilitate studies of the amyloid-beta (A beta) peptide in monomeric form : Low pH was found to reduce A beta/Cu(II) binding affinity
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- Lindgren, Joel (author)
- KTH,Molekylär Bioteknologi
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- Segerfeldt, Patrik (author)
- KTH,Molekylär Bioteknologi
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- Sholts, Sabrina B. (author)
- Stockholms universitet,Institutionen för biokemi och biofysik
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- Gräslund, Astrid (author)
- Stockholms universitet,Institutionen för biokemi och biofysik
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- Eriksson Karlström, Amelie (author)
- KTH,Molekylär Bioteknologi
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- Wärmländer, Sebastian K. T. S. (author)
- Stockholms universitet,Institutionen för biokemi och biofysik
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(creator_code:org_t)
- Elsevier BV, 2013
- 2013
- English.
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In: Journal of Inorganic Biochemistry. - : Elsevier BV. - 0162-0134 .- 1873-3344. ; 120, s. 18-23
- Related links:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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https://urn.kb.se/re...
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Abstract
Subject headings
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- Aggregation of amyloid-beta (A beta) peptides into oligomers and amyloid plaques in the human brain is considered a causative factor in Alzheimer's disease (AD). As metal ions are over-represented in AD patient brains, and as distinct A beta aggregation pathways in presence of Cu(II) have been demonstrated, metal binding to A beta likely affects AD progression. A beta aggregation is moreover pH-dependent, and AD appears to involve inflammatory conditions leading to physiological acidosis. Although metal binding specificity to A beta varies at different pH's, metal binding affinity to A beta has so far not been quantitatively investigated at sub-neutral pH levels. This may be explained by the difficulties involved in studying monomeric peptide properties under aggregation-promoting conditions. We have recently devised a modified Affibody molecule, Z(A beta 3)(12-58), that binds A beta with sub-nanomolar affinity, thereby locking the peptide in monomeric form without affecting the N-terminal region where metal ions bind. Here, we introduce non-fluorescent A beta-binding Affibody variants that keep A beta monomeric while only slightly affecting the A beta peptide's metal binding properties. Using fluorescence spectroscopy, we demonstrate that Cu(II)/A beta(1-40) binding is almost two orders of magnitude weaker at pH 5.0 (apparent K-D = 51 mu M) than at pH 7.3 (apparent K-D = 0.86 mu M). This effect is arguably caused by protonation of the histidines involved in the metal ligandation. Our results indicate that engineered variants of Affibody molecules are useful for studying metal-binding and other properties of monomeric A beta under various physiological conditions, which will improve our understanding of the molecular mechanisms involved in AD.
Subject headings
- NATURVETENSKAP -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)
Keyword
- Alzheimer's disease
- Affibody molecule
- Copper ion
- Binding constant
- Protein engineering
- Peptide aggregation
Publication and Content Type
- ref (subject category)
- art (subject category)
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