Methylglyoxal modification hinders amyloid conversion of prion protein

Effect of glycation by methylglyoxal on prion protein (PrP) structure and properties was evaluated. Modification of arginine at 27-position into a hydroimidazolone derivative was confirmed by MALDI-TOF mass spectrometry; circular dichroism spectra and tryptophan fluorescence showed some structural changes, while the hydrodynamic diameter of PrP was not affected by glycation. Glycated PrP formed large amorphous aggregates instead of intermediate oligomers; seeding of glycated PrP by mature fibrils led to a decreased formation of amyloid structures.