Vanadium-Substituted Polyoxometalates Regulate Prion Protein Fragment 106-126 Misfolding by an Oxidation Strategy

Prion disorders are a group of lethal infectious neurodegenerative diseases caused by the spontaneous aggregation of misfolded prion proteins (PrP^Sc). The oxidation of such proteins by chemical reagents can significantly modulate their aggregation behavior. Herein, we exploit a series of vanadium-substituted Keggin-type tungsten and molybdenum POMs (W- and Mo-POMs) as chemical tools to oxidize PrP106-126 (denoted as PrP), an ideal model for studying PrP^Sc. Due to the band gaps being larger than that of Mo-POMs, W-POMs possess higher structural stability and show stronger binding and oxidation effect on PrP. Additionally, the substitution of W/Mo by vanadium elevates the local electron distribution on the bridged O(26) atom, thereby strengthening the hydrogen bonding of POMs with the histidine site. Most importantly, with the number of substituted vanadium increases, the LUMO energy level of POMs decreases, making it easier to accept electrons from methionine. As a result, PW₁₀V₂ displays the strongest oxidation on the methionine residue of PrP, leading to an excellent inhibitory effect on PrP aggregation and a significant attenuation on its neurotoxicity.