Even though amyloid aggregates were discovered many years ago the mechanism of their formation is still a mystery. Because of their connection to many of untreatable neurodegenerative diseases the motivation for finding a common aggregation path is high. We report a new high heat induced fibrillization path of a model protein β-lactoglobulin (BLG) when incubated in glycine instead of water at pH 2. By combining atomic force microscopy (AFM), transmission emission microscopy (TEM), dynamic light scattering (DLS) and circular dichroism (CD) we predict that the basic building blocks of fibrils made in glycine are not peptides, but rather spheroid oligomers of different height that form by stacking of ring-like structures. Spheroid oligomers linearly align to form fibrils by opening up and combining. We suspect that glycine acts as an hydrolysation inhibitor which consequently promotes a different fibrillization path. By combining the known data on fibrillization in water with our experimental conclusions we come up with a new fibrillization scheme for BLG. We show that by changing the fibrillization conditions just by small changes in buffer composition can dramatically change the aggregation pathway and the effect of buffer shouldn't be neglected. Fibrils seen in our study are also gaining more and more attention because of their pore-like structure and a possible cytotoxic mechanism by forming pernicious ion-channels. By preparing them in a simple model system as BLG we opened a new way to study their formation.

• Klíčová slova
• Buffer specific effects, Fibrillization mechanism, Spheroid oligomers, β-lactoglobulin,
• MeSH
• amyloid * chemie   MeSH
• glycin farmakologie   MeSH
• laktoglobuliny * chemie   MeSH
• mikroskopie atomárních sil metody   MeSH
• voda MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• amyloid * MeSH
• glycin MeSH
• laktoglobuliny * MeSH
• voda MeSH

Glycation is a process closely related to the aging and pathogenesis of diabetic complications. Reactive alpha-dicarbonyl compounds (e.g., methylglyoxal) are formed during middle stage of glycation reaction. Compounds that would inhibit the glycation process have been seeked for years. The objective of this study was to investigate the inhibitory effect of hydroxycitric (0.25-2.5 mM) and uric acid (0.4-1.2 mM) on middle stage of protein glycation in vitro using the model containing aspartate aminotransferase (AST) and 0.5 mM methylglyoxal. Hydroxycitric acid, at all tested concentrations, reduced AST activity decrease and formation of fluorescent AGEs during incubation of the enzyme with methylglyoxal at 37 degrees C. This compound also prevented formation of high-molecular weight protein cross-links and changes in molecular charge of AST caused by glycation. Uric acid showed no positive anti-glycation activity. The results support the hypothesis that hydroxycitric acid has beneficial effects in controlling protein glycation.

• MeSH
• aspartátaminotransferasy chemie   metabolismus   MeSH
• citráty farmakologie   MeSH
• fluorescence MeSH
• glykosylace účinky léků   MeSH
• kvarterní struktura proteinů MeSH
• kyselina močová farmakologie   MeSH
• ornithin analogy a deriváty   metabolismus   MeSH
• produkty pokročilé glykace metabolismus   MeSH
• pyrimidiny metabolismus   MeSH
• pyruvaldehyd farmakologie   MeSH
• reagencia zkříženě vázaná farmakologie   MeSH
• Sus scrofa MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• argpyrimidine MeSH Prohlížeč
• aspartátaminotransferasy MeSH
• citráty MeSH
• hydroxycitric acid MeSH Prohlížeč
• kyselina močová MeSH
• ornithin MeSH
• produkty pokročilé glykace MeSH
• pyrimidiny MeSH
• pyruvaldehyd MeSH
• reagencia zkříženě vázaná MeSH