Tissue transglutaminase modulates alpha-synuclein oligomerization

Gezina M.J. Segers-Nolten, Micha M.M. Wilhelmus, G.J. Veldhuis, G. Veldhuis, Bart van Rooijen, Benjamin Drukarch, Vinod Subramaniam

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We have studied the interaction of the enzyme tissue transglutaminase (tTG), catalyzing cross-link formation between protein-bound glutamine residues and primary amines, with Parkinson's disease-associated α-synuclein protein variants at physiologically relevant concentrations. We have, for the first time, determined binding affinities of tTG for wild-type and mutant α-synucleins using surface plasmon resonance approaches, revealing high-affinity nanomolar equilibrium dissociation constants. Nanomolar tTG concentrations were sufficient for complete inhibition of fibrillization by effective α-synuclein cross-linking, resulting predominantly in intramolecularly cross-linked monomers accompanied by an oligomeric fraction. Since oligomeric species have a pathophysiological relevance we further investigated the properties of the tTG/α-synuclein oligomers. Atomic force microscopy revealed morphologically similar structures for oligomers from all α-synuclein variants; the extent of oligomer formation was found to correlate with tTG concentration. Unlike normal α-synuclein oligomers the resultant structures were extremely stable and resistant to GdnHCl and SDS. In contrast to normal β-sheet-containing oligomers, the tTG/α-synuclein oligomers appear to be unstructured and are unable to disrupt phospholipid vesicles. These data suggest that tTG binds equally effective to wild-type and disease mutant α-synuclein variants. We propose that tTG cross-linking imposes structural constraints on α-synuclein, preventing the assembly of structured oligomers required for disruption of membranes and for progression into fibrils. In general, cross-linking of amyloid forming proteins by tTG may prevent the progression into pathogenic species.
Original languageUndefined
Pages (from-to)1395-1402
Number of pages8
JournalProtein science
Issue number8
Publication statusPublished - 2008


  • Parkinson's Disease
  • oligomer
  • Surface plasmon resonance
  • tissue transglutaminase
  • α-Synuclein
  • METIS-248984
  • IR-72349
  • Cross-linking
  • Atomic Force Microscopy

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