Cristine Betzer

Characterizing the dynamics of alpha-synuclein oligomers using hydrogen/deuterium exchange monitored by mass spectrometry

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  • Simon Mysling, Institut for Biokemi og Molekylær Biologi, Denmark
  • Cristine Betzer
  • Poul H Jensen
  • Thomas J. D. Jørgensen, Institut for Biokemi og Molekylær Biologi, Denmark
Soluble oligomers formed by alpha-synuclein (αSN) are suspected to play a central role in neuronal cell death during Parkinson's Disease. While studies have probed the surface structure of these oligomers, little is known about the backbone dynamics of αSN when forming soluble oligomers. Using hydrogen/deuterium exchange monitored by mass spectrometry (HDX-MS), we have analyzed the structural dynamics of soluble αSN oligomers. The analyzed oligomers were metastable, slowly dissociating to monomers over a period of 21 days, after excess monomer had been removed. The C-terminal region of αSN (residues 94 - 140) underwent isotopic exchange very rapidly, demonstrating a highly dynamic region in the oligomeric state. Three regions (residues 4-17, 39-54 and 70-89) were strongly protected against isotopic exchange in the oligomers, indicating the presence of a stable hydrogen bonded or solvent shielded structure. The protected regions were interspersed by two somewhat more dynamic regions (residues 18-38 and 55-70). In the oligomeric state, the isotopic exchange pattern of the 35-95 region of αSN corresponded well with previous nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) analyses performed on αSN fibrils, and indicated a possible zipper-like maturation mechanism for αSN aggregates. We find the protected N-terminus (residues 4-17) to be of particular interest, as this region has previously been observed to be highly dynamic for both monomeric and fibrillar αSN . This region has mainly been described in relation to membrane-binding of αSN and structuring may be important in relation to disease.
Original languageEnglish
Publication statusPublished - 5 Nov 2013

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