[13] Methodological and chemical factors affecting amyloid β peptide amyloidogenicity

Zagorski, Michael G.; Yang, Jing; Shao, Huili; Ma, Ke; Zeng, Hong; Hong, Anita

doi:10.1016/s0076-6879(99)09015-1

Cited by 182 publications

(191 citation statements)

References 26 publications

Supporting

Mentioning

181

Contrasting

Unclassified

Order By: Relevance

“…We now show that A␤ aggregates are formed rapidly in dilute HFIP, and these aggregates exhibit a dramatically broader range of stability. HFIP is widely known as an effective solvent for A␤ peptides (52). A␤-(1-40) protofibrils and fibrils were solubilized at HFIP concentrations above 20% (v/v), as indicated by loss of thioflavin T fluorescence and conversion to monomeric A␤ on SEC (data not shown).…”

Section: Resultsmentioning

confidence: 96%

Amyloid-β Protofibrils Differ from Amyloid-β Aggregates Induced in Dilute Hexafluoroisopropanol in Stability and Morphology

Nichols

Moss

Reed

et al. 2005

Journal of Biological Chemistry

108

129

View full text Add to dashboard Cite

) followed by a much slower secondary phase. Incubation of the reactions without agitation resulted in less disaggregation at slower rates, indicating that the protofibrils became progressively more stable over time. In fact, protofibrils isolated by size exclusion chromatography were completely stable and gave no disaggregation. A second class of soluble A␤ aggregates was generated rapidly (<10 min) in buffered 2% hexafluoroisopropanol (HFIP). These aggregates showed increased thioflavin T fluorescence and were rich in ␤-structure by circular dichroism. Electron microscopy and atomic force microscopy revealed initial globular clusters that progressed over several days to soluble fibrous aggregates. When diluted out of HFIP, these aggregates initially were very unstable and disaggregated completely within 2 min. However, their stability increased as they progressed to fibers. Relative to A␤ protofibrils, the HFIP-induced aggregates seeded elongation by A␤ monomer deposition very poorly. The techniques used to distinguish these two classes of soluble A␤ aggregates may be useful in characterizing A␤ aggregates formed in vivo.

show abstract

Section: Resultsmentioning

confidence: 96%

Amyloid-β Protofibrils Differ from Amyloid-β Aggregates Induced in Dilute Hexafluoroisopropanol in Stability and Morphology

Nichols

Moss

Reed

et al. 2005

Journal of Biological Chemistry

108

129

View full text Add to dashboard Cite

show abstract

“…The approach outlined in this protocol ensures that the recovered peptide fractions are free of any fibrillar material and variability among different Aβ preparations is minimized. Finally, to circumvent any potential problems associated with the use of sAβ peptides (such as impurities, racemization, salts or trace metals introduced during peptide synthesis and purification 52 ), many laboratories have developed methods for the expression of recombinant Aβ (rAβ) in E. coli [75][76][77] . rAβ peptides have been shown to exhibit similar or higher toxicity compared with sAβ 75,76 .…”

Section: Centrifugedmentioning

confidence: 99%

“…Treatment of lyophilized Aβ with strong acids and bases to disrupt preformed aggregates and enhance solubility 52 , filtration through LMW cutoff filters 53 , photo-induced crosslinking of unmodified proteins 17 , density gradient centrifugation 54 and size exclusion chromatography (SEC) 13,14,17 have all been used to prepare soluble aggregates of Aβ and yield preparations that vary in size and morphology distribution. SEC, in particular, offers several advantages: (i) a variety of column matrices with different separation capacities are readily available and can be used in isolation or in combination with other columns to obtain high-resolution separation and fractions containing Aβ aggregates of defined size distribution; (ii) generally, the columns are equipped with filters at the top that allow for the removal of fibrillar (or insoluble) material from the injected sample, thus ensuring that the Aβ fractions are free of fibrillar seeds; (iii) if SEC is coupled to a light-scattering detector, accurate determination of Aβ aggregates' size distribution becomes possible 20 ; (iv) in analytical mode, SEC is a valuable tool to monitor early events in amyloid formation and quantification of monomer and/or protofibril loss during the time course of fibril formation 21 ; and (v) by choosing proper running conditions (i.e., buffer pH and contents), fractions are obtained in solution conditions suitable for biological systems, free of harmful or undesired substances (e.g., organic solvents and so on).…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of toxic Aβ aggregates for structural and functional studies in Alzheimer's disease research

2010

View full text Add to dashboard Cite

“…Amyloid plaques found in AD patients contain a 39-42-residue peptide, -amyloid (A ), that is highly prone to aggregation under appropriate conditions (6). The natural function of A is unknown.…”

mentioning

confidence: 99%

Affinity-Based Inhibition of β-Amyloid Toxicity

et al. 2002

View full text Add to dashboard Cite

Strategies for interfering with protein aggregation are important for elucidating and controlling the pathologies of amyloid diseases. We have previously identified compounds that block the cellular toxicity of the -amyloid peptide, but the relationship between their ability to inhibit toxicity and their affinity for A is unknown. To elucidate this relationship, we have developed an assay capable of measuring the affinities of small molecules for -amyloid peptide. Our approach employs immobilized -amyloid peptide at low density to minimize the problems that arise from variability in the -amyloid aggregation state. We found that low-molecular weight (MW of 700-1700) ligands for -amyloid can be identified readily by using surface plasmon resonance. The best of these bound effectively (K d ∼ 40 µM) to -amyloid. The affinities measured for peptides in the SPR assay correspond to results from A cell toxicity assays. The most potent ligands for immobilized -amyloid are the most potent inhibitors of the neuronal cell toxicity of -amyloid. Compounds with dissocation constants above ∼100 µΜ did not show significant activity in the cell toxicity assays. Our data support the hypothesis that ligands exhibiting greater affinity for the -amyloid peptide are effective at altering its aggregation and inhibiting cell toxicity.

show abstract

[13] Methodological and chemical factors affecting amyloid β peptide amyloidogenicity

Cited by 182 publications

References 26 publications

Amyloid-β Protofibrils Differ from Amyloid-β Aggregates Induced in Dilute Hexafluoroisopropanol in Stability and Morphology

Amyloid-β Protofibrils Differ from Amyloid-β Aggregates Induced in Dilute Hexafluoroisopropanol in Stability and Morphology

Preparation and characterization of toxic Aβ aggregates for structural and functional studies in Alzheimer's disease research

Affinity-Based Inhibition of β-Amyloid Toxicity

Contact Info

Product

Resources

About