The Off-rate of Monomers Dissociating from Amyloid-β Protofibrils

被引:24
|
作者
Gruening, Clara S. R. [1 ]
Klinker, Stefan [1 ]
Wolff, Martin [1 ,2 ]
Schneider, Mario [1 ]
Toksoez, Kuepra [1 ]
Klein, Antonia N. [2 ]
Nagel-Steger, Luitgard [1 ,2 ]
Willbold, Dieter [1 ,2 ]
Hoyer, Wolfgang [1 ,2 ]
机构
[1] Univ Dusseldorf, Inst Phys Biol, D-40204 Dusseldorf, Germany
[2] Res Ctr Julich, Inst Struct Biochem ICS 6, D-52425 Julich, Germany
关键词
Alzheimer Disease; Amyloid; Fluorescence; Kinetics; Protein Aggregation; Protein Engineering; Protein Misfolding; Scaffold Proteins; Spectroscopy; PROTEIN FIBRILLOGENESIS; PEPTIDE; A-BETA-40; THERMODYNAMICS; FLUORESCENCE; MECHANISMS; OLIGOMERS; KINETICS; BINDING;
D O I
10.1074/jbc.M113.513432
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The interconversion of monomers, oligomers, and amyloid fibrils of the amyloid- peptide (A) has been implicated in the pathogenesis of Alzheimer disease. The determination of the kinetics of the individual association and dissociation reactions is hampered by the fact that forward and reverse reactions to/from different aggregation states occur simultaneously. Here, we report the kinetics of dissociation of A monomers from protofibrils, prefibrillar high molecular weight oligomers previously shown to possess pronounced neurotoxicity. An engineered binding protein sequestering specifically monomeric A was employed to follow protofibril dissociation by tryptophan fluorescence, precluding confounding effects of reverse or competing reactions. A protofibril dissociation into monomers follows exponential decay kinetics with a time constant of approximate to 2 h at 25 degrees C and an activation energy of 80 kJ/mol, values typical for high affinity biomolecular interactions. This study demonstrates the high kinetic stability of A protofibrils toward dissociation into monomers and supports the delineation of the A folding and assembly energy landscape.
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页码:37104 / 37111
页数:8
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