Abstract
Originalsprog | Engelsk |
---|---|
Tidsskrift | Biochemistry |
Vol/bind | 44 |
Udgave nummer | 11 |
Sider (fra-til) | 4397-407 |
Antal sider | 10 |
ISSN | 0006-2960 |
DOI | |
Status | Udgivet - 2005 |
Bibliografisk note
Keywords: Amyloid; Binding Sites; Chromatography, Gel; Congo Red; Deuterium Exchange Measurement; Electrophoresis, Capillary; Fluorescent Dyes; Humans; Hydrolysis; Lysine; Microscopy, Atomic Force; Protein Conformation; Protein Folding; Spectrometry, Fluorescence; Spectrometry, Mass, Electrospray Ionization; Temperature; Thiazoles; Time Factors; beta 2-MicroglobulinAdgang til dokumentet
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I: Biochemistry, Bind 44, Nr. 11, 2005, s. 4397-407.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
}
TY - JOUR
T1 - Unfolding, aggregation, and seeded amyloid formation of lysine-58-cleaved beta 2-microglobulin.
AU - Heegaard, Niels H H
AU - Jørgensen, Thomas J D
AU - Rozlosnik, Noémi
AU - Corlin, Dorthe B
AU - Pedersen, Jesper S
AU - Tempesta, Anna G
AU - Roepstorff, Peter
AU - Bauer, Rogert
AU - Nissen, Mogens H
N1 - Keywords: Amyloid; Binding Sites; Chromatography, Gel; Congo Red; Deuterium Exchange Measurement; Electrophoresis, Capillary; Fluorescent Dyes; Humans; Hydrolysis; Lysine; Microscopy, Atomic Force; Protein Conformation; Protein Folding; Spectrometry, Fluorescence; Spectrometry, Mass, Electrospray Ionization; Temperature; Thiazoles; Time Factors; beta 2-Microglobulin
PY - 2005
Y1 - 2005
N2 - Beta(2)-microglobulin (beta(2)m) is the amyloidogenic protein in dialysis-related amyloidosis, but the mechanisms underlying beta(2)m fibrillogenesis in vivo are largely unknown. We study a structural variant of beta(2)m that has been linked to cancer and inflammation and may be present in the circulation of dialysis patients. This beta(2)m variant, DeltaK58-beta(2)m, is a disulfide-linked two-chain molecule consisting of amino acid residues 1-57 and 59-99 of intact beta(2)m, and we here demonstrate and characterize its decreased conformational stability as compared to wild-type (wt) beta(2)m. Using amide hydrogen/deuterium exchange monitored by mass spectrometry, we show that DeltaK58-beta(2)m has increased unfolding rates compared to wt-beta(2)m and that unfolding is highly temperature dependent. The unfolding rate is 1 order of magnitude faster in DeltaK58-beta(2)m than in wt-beta(2)m, and at 37 degrees C the half-time for unfolding is more than 170-fold faster than at 15 degrees C. Conformational changes are also reflected by a very prominent Congo red binding of DeltaK58-beta(2)m at 37 degrees C, by the evolution of thioflavin T fluorescence, and by changes in intrinsic fluorescence. After a few days at 37 degrees C, in contrast to wt-beta(2)m, DeltaK58-beta(2)m forms well-defined high molecular weight aggregates that are detected by size-exclusion chromatography. Atomic force microscopy after seeding with amyloid-beta(2)m fibrils under conditions that induce minimal fibrillation in wt-beta(2)m shows extensive amyloid fibrillation in DeltaK58-beta(2)m samples. The results highlight the instability and amyloidogenicity under near physiological conditions of a slightly modified beta(2)m variant generated by limited proteolysis and illustrate stages of amyloid formation from early conformational variants to overt fibrillation.
AB - Beta(2)-microglobulin (beta(2)m) is the amyloidogenic protein in dialysis-related amyloidosis, but the mechanisms underlying beta(2)m fibrillogenesis in vivo are largely unknown. We study a structural variant of beta(2)m that has been linked to cancer and inflammation and may be present in the circulation of dialysis patients. This beta(2)m variant, DeltaK58-beta(2)m, is a disulfide-linked two-chain molecule consisting of amino acid residues 1-57 and 59-99 of intact beta(2)m, and we here demonstrate and characterize its decreased conformational stability as compared to wild-type (wt) beta(2)m. Using amide hydrogen/deuterium exchange monitored by mass spectrometry, we show that DeltaK58-beta(2)m has increased unfolding rates compared to wt-beta(2)m and that unfolding is highly temperature dependent. The unfolding rate is 1 order of magnitude faster in DeltaK58-beta(2)m than in wt-beta(2)m, and at 37 degrees C the half-time for unfolding is more than 170-fold faster than at 15 degrees C. Conformational changes are also reflected by a very prominent Congo red binding of DeltaK58-beta(2)m at 37 degrees C, by the evolution of thioflavin T fluorescence, and by changes in intrinsic fluorescence. After a few days at 37 degrees C, in contrast to wt-beta(2)m, DeltaK58-beta(2)m forms well-defined high molecular weight aggregates that are detected by size-exclusion chromatography. Atomic force microscopy after seeding with amyloid-beta(2)m fibrils under conditions that induce minimal fibrillation in wt-beta(2)m shows extensive amyloid fibrillation in DeltaK58-beta(2)m samples. The results highlight the instability and amyloidogenicity under near physiological conditions of a slightly modified beta(2)m variant generated by limited proteolysis and illustrate stages of amyloid formation from early conformational variants to overt fibrillation.
U2 - 10.1021/bi047594t
DO - 10.1021/bi047594t
M3 - Journal article
C2 - 15766269
SN - 0006-2960
VL - 44
SP - 4397
EP - 4407
JO - Biochemistry
JF - Biochemistry
IS - 11
ER -