Formation of a high affinity lipid-binding intermediate during the early aggregation phase of α-synuclein

SMITH, David P., TEW, Deborah J., HILL, Andrew F., BOTTOMLEY, Stephen P., MASTERS, Colin L., BARNHAM, Kevin J. and CAPPAI, Roberto (2008). Formation of a high affinity lipid-binding intermediate during the early aggregation phase of α-synuclein. Biochemistry, 47 (5), 1425-1434.

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Official URL: http://dx.doi.org/10.1021/bi701522m
Link to published version:: 10.1021/bi701522m

Abstract

The alpha-synuclein (alpha-syn) protein is clearly implicated in Parkinson's disease (PD). Mutations or triplication of the alpha-syn gene leads to early onset PD, possibly by accelerating alpha-syn oligomerization. alpha-syn interacts with lipids, and this membrane binding activity may relate to its toxic activity. To understand how the alpha-syn aggregation state affects its lipid binding activity we used surface plasmon resonance to study the interaction of wild-type and mutant alpha-syn with a charged phospholipid membrane, as a function of its aggregation state. Apparent dissociation constants for alpha-syn indicated that an intermediate species, present during the lag phase of amyloid formation, binds with an increased affinity to the membrane surface. Formation of this species was dependent upon the rate of fibril formation. Fluorescence anisotropy studies indicate that only upon the formation of amyloid material can alpha-syn perturb the acyl-chain region of the lipid bilayer. Circular dichroism spectroscopy showed that upon aging, both wild-type and mutant alpha-syn lose their ability to form lipid-bound alpha-helical species once they become fibrillar. These results indicate that alpha-syn forms a high affinity lipid binding intermediate species during fibril formation. Oligomeric alpha-syn is known to be toxic, and it is feasible that the high affinity binding species described here may correspond to a toxic species involved in PD.

Item Type: Article
Research Institute, Centre or Group: Biomedical Research Centre
Identification Number: 10.1021/bi701522m
Depositing User: Rebecca Jones
Date Deposited: 01 Mar 2012 09:40
Last Modified: 01 Mar 2012 09:40
URI: http://shura.shu.ac.uk/id/eprint/4884

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