A soluble α-synuclein construct forms a dynamic tetramer

Proc Natl Acad Sci U S A. 2011 Oct 25;108(43):17797-802. doi: 10.1073/pnas.1113260108. Epub 2011 Oct 17.

Abstract

A heterologously expressed form of the human Parkinson disease-associated protein α-synuclein with a 10-residue N-terminal extension is shown to form a stable tetramer in the absence of lipid bilayers or micelles. Sequential NMR assignments, intramonomer nuclear Overhauser effects, and circular dichroism spectra are consistent with transient formation of α-helices in the first 100 N-terminal residues of the 140-residue α-synuclein sequence. Total phosphorus analysis indicates that phospholipids are not associated with the tetramer as isolated, and chemical cross-linking experiments confirm that the tetramer is the highest-order oligomer present at NMR sample concentrations. Image reconstruction from electron micrographs indicates that a symmetric oligomer is present, with three- or fourfold symmetry. Thermal unfolding experiments indicate that a hydrophobic core is present in the tetramer. A dynamic model for the tetramer structure is proposed, based on expected close association of the amphipathic central helices observed in the previously described micelle-associated "hairpin" structure of α-synuclein.

Publication types

  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • Humans
  • Microscopy, Electron
  • Models, Molecular*
  • Nuclear Magnetic Resonance, Biomolecular
  • Polymers / chemistry*
  • Protein Structure, Secondary*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • alpha-Synuclein / chemistry*

Substances

  • Polymers
  • alpha-Synuclein