The Impact of the E46K Mutation on the Properties of -Synuclein in Its Monomeric and Oligomeric States
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- 作者：Ross A. Fredenburg ; Carla Rospigliosi ; Robin K. Meray ; Jeffrey C. Kessler ; Hilal A. Lashuel ; David Eliezer ; Peter T. Lansbury ; Jr.
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：June 19, 2007
- 年：2007
- 卷：46
- 期：24
- 页码：7107 - 7118
- 全文大小：655K
- 年卷期：v.46,no.24(June 19, 2007)
- ISSN：1520-4995
文摘
The third and most recently identified Parkinson's disease-linked variant of the neuronal protein
-synuclein to be identified (E46K) results in widespread brain pathology and early onset Parkinsonsymptoms (Zarranz et al. (2004) Ann. Neurol. 55, 164-173). Herein, we present biochemical andbiophysical characterization of E46K -synuclein in various states of aggregation. Circular dichroismand nuclear magnetic resonance spectroscopy illustrate that the E46K mutation results in subtle changesin the conformation of the monomeric protein both free in solution and in the presence of SDS micelles.However, it does not alter the overall helical propensity of the protein in the presence of phospholipids.E46K -synuclein formed insoluble fibrils in vitro more rapidly than the wild type protein, and electronmicroscopy revealed that E46K -synuclein fibrils possess a typical amyloid ultrastructure. E46K-synuclein protofibrils, soluble aggregates that form during the transition from the monomeric form tothe fibrillar form of -synuclein, were characterized by electron microscopy and gel filtration and werefound to include annular species. The unique ability of a subfraction of E46K and wild type -synucleinprotofibrils containing porelike species to permeabilize lipid vesicles was demonstrated in vitro using areal-time chromatographic method. In contrast to simplistic expectations, the total amount of protofibrilsand the amount of permeabilizing activity per mole protein in the protofibril fraction were reduced by theE46K mutation. These results suggest that if the porelike activity of -synuclein is important forneurotoxicity, there must be factors in the neuronal cytoplasm that reverse the trends in the intrinsicproperties of E46K versus WT -synuclein that are observed in vitro.
-synuclein to be identified (E46K) results in widespread brain pathology and early onset Parkinsonsymptoms (Zarranz et al. (2004) Ann. Neurol. 55, 164-173). Herein, we present biochemical andbiophysical characterization of E46K -synuclein in various states of aggregation. Circular dichroismand nuclear magnetic resonance spectroscopy illustrate that the E46K mutation results in subtle changesin the conformation of the monomeric protein both free in solution and in the presence of SDS micelles.However, it does not alter the overall helical propensity of the protein in the presence of phospholipids.E46K -synuclein formed insoluble fibrils in vitro more rapidly than the wild type protein, and electronmicroscopy revealed that E46K -synuclein fibrils possess a typical amyloid ultrastructure. E46K-synuclein protofibrils, soluble aggregates that form during the transition from the monomeric form tothe fibrillar form of -synuclein, were characterized by electron microscopy and gel filtration and werefound to include annular species. The unique ability of a subfraction of E46K and wild type -synucleinprotofibrils containing porelike species to permeabilize lipid vesicles was demonstrated in vitro using areal-time chromatographic method. In contrast to simplistic expectations, the total amount of protofibrilsand the amount of permeabilizing activity per mole protein in the protofibril fraction were reduced by theE46K mutation. These results suggest that if the porelike activity of -synuclein is important forneurotoxicity, there must be factors in the neuronal cytoplasm that reverse the trends in the intrinsicproperties of E46K versus WT -synuclein that are observed in vitro.