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A label-free high-throughput protein solubility assay and its application to Aβ40

Lindberg, Max LU ; Axell, Emil LU ; Sparr, Emma LU and Snogerup-Linse, Sara LU (2024) In Biophysical Chemistry
Abstract
A major hallmark of Alzheimer's disease is the accumulation of aggregated amyloid peptide (Aβ) in the brain. Here we develop a solubility assay for proteins and measure the solubility of Aβ40. In brief, the method utilizes 96-well filter plates to separate monomeric Aβ from aggregated Aβ, and the small species are quantified with the amine reactive dye o-phthalaldehyde (OPA). This procedure ensures that solubility is measured for unlabeled species, and makes the assay high-throughput and inexpensive. We demonstrate that the filter plates successfully separate fibrils from monomer, with negligible monomer adsorption, and that OPA can quantify Aβ peptides in a concentration range from 44 nM to 20 μM. We also show that adding a methionine... (More)
A major hallmark of Alzheimer's disease is the accumulation of aggregated amyloid peptide (Aβ) in the brain. Here we develop a solubility assay for proteins and measure the solubility of Aβ40. In brief, the method utilizes 96-well filter plates to separate monomeric Aβ from aggregated Aβ, and the small species are quantified with the amine reactive dye o-phthalaldehyde (OPA). This procedure ensures that solubility is measured for unlabeled species, and makes the assay high-throughput and inexpensive. We demonstrate that the filter plates successfully separate fibrils from monomer, with negligible monomer adsorption, and that OPA can quantify Aβ peptides in a concentration range from 44 nM to 20 μM. We also show that adding a methionine residue to the N-terminus of Aβ1–40 decreases the solubility by <3-fold. The method will facilitate further solubility studies, and contribute to the understanding of the thermodynamics of amyloid fibril formation. (Less)
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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
in
Biophysical Chemistry
publisher
Elsevier
external identifiers
  • scopus:85184008680
ISSN
0301-4622
DOI
10.1016/j.bpc.2023.107165
language
English
LU publication?
yes
id
59d15558-9c4d-4120-a07f-e0d52403ef99
date added to LUP
2024-01-29 10:22:29
date last changed
2024-03-05 12:12:54
@article{59d15558-9c4d-4120-a07f-e0d52403ef99,
  abstract     = {{A major hallmark of Alzheimer's disease is the accumulation of aggregated amyloid peptide (Aβ) in the brain. Here we develop a solubility assay for proteins and measure the solubility of Aβ40. In brief, the method utilizes 96-well filter plates to separate monomeric Aβ from aggregated Aβ, and the small species are quantified with the amine reactive dye o-phthalaldehyde (OPA). This procedure ensures that solubility is measured for unlabeled species, and makes the assay high-throughput and inexpensive. We demonstrate that the filter plates successfully separate fibrils from monomer, with negligible monomer adsorption, and that OPA can quantify Aβ peptides in a concentration range from 44 nM to 20 μM. We also show that adding a methionine residue to the N-terminus of Aβ1–40 decreases the solubility by &lt;3-fold. The method will facilitate further solubility studies, and contribute to the understanding of the thermodynamics of amyloid fibril formation.}},
  author       = {{Lindberg, Max and Axell, Emil and Sparr, Emma and Snogerup-Linse, Sara}},
  issn         = {{0301-4622}},
  language     = {{eng}},
  month        = {{01}},
  publisher    = {{Elsevier}},
  series       = {{Biophysical Chemistry}},
  title        = {{A label-free high-throughput protein solubility assay and its application to A<i>β</i>40}},
  url          = {{http://dx.doi.org/10.1016/j.bpc.2023.107165}},
  doi          = {{10.1016/j.bpc.2023.107165}},
  year         = {{2024}},
}