The role of conformational flexibility in β2-microglobulin amyloid fibril formation at neutral pH

Copyright © 2012 John Wiley & Sons, Ltd..

RATIONALE: Amyloid formation is implicated in a number of human diseases. β(2)-Microglobulin (β(2)m) is the precursor protein in dialysis-related amyloidosis and it has been shown that partial, or more complete, unfolding is key to amyloid fibril formation in this pathology. Here the relationship between conformational flexibility and β(2)m amyloid formation at physiological pH has been investigated.

METHODS: HDX-ESI-MS was used to study the conformational dynamics of β(2)m. Protein engineering, or the addition of Cu(2+) ions, sodium dodecyl sulphate, trifluoroethanol, heparin, or protein stabilisers, was employed to perturb the conformational dynamics of β(2)m. The fibril-forming propensities of the protein variants and the wild-type protein in the presence of additives, which resulted in >5-fold increase in the EX1 rate of HDX, were investigated further.

RESULTS: ESI-MS revealed that HDX occurs via a mixed EX1/EX2 mechanism under all conditions. Urea denaturation and tryptophan fluorescence indicated that EX1 exchange occurred from a globally unfolded state in wild-type β(2)m. Although >30-fold increase in the HDX exchange rate was observed both for the protein variants and for the wild-type protein in the presence of specific additives, large increases in exchange rate did not necessarily result in extensive de novo fibril formation.

CONCLUSIONS: The conformational dynamics measured by the EX1 rate of HDX do not predict the ability of β(2)m to form amyloid fibrils de novo at neutral pH. This suggests that the formation of amyloid fibrils from β(2)m at neutral pH is dependent on the generation of one or more specific aggregation-competent species which facilitate self-assembly.

Medienart:

E-Artikel

Erscheinungsjahr:

2012

Erschienen:

2012

Enthalten in:

Zur Gesamtaufnahme - volume:26

Enthalten in:

Rapid communications in mass spectrometry : RCM - 26(2012), 16 vom: 30. Aug., Seite 1783-92

Sprache:

Englisch

Beteiligte Personen:

Hodkinson, John P [VerfasserIn]
Radford, Sheena E [VerfasserIn]
Ashcroft, Alison E [VerfasserIn]

Links:

Volltext

Themen:

368GB5141J
75-89-8
Amyloid
B8WCK70T7I
Beta 2-Microglobulin
Calcium
Journal Article
Research Support, Non-U.S. Gov't
SY7Q814VUP
Sarcosine
Sodium Dodecyl Sulfate
Trehalose
Trifluoroethanol
Z711V88R5F

Anmerkungen:

Date Completed 09.10.2012

Date Revised 21.10.2021

published: Print

Citation Status MEDLINE

doi:

10.1002/rcm.6282

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM219283001