Protein-Assisted Formation and Stabilization of Catalytically Active Polyoxometalate Species

The effect of the protein environment on the formation and stabilization of an elusive catalytically active polyoxometalate (POM) species, K6 [Hf(α2 -P2 W17 O61 )] (1), is reported. In the co-crystal of hen egg-white lysozyme (HEWL) with 1, the catalytically active monomeric species is observed, ori...

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Veröffentlicht in:CHEMISTRY-A EUROPEAN JOURNAL 2018-07, Vol.24 (40), p.10099-10108
Hauptverfasser: Vandebroek, Laurens, De Zitter, Elke, Hong, Giang Thi Ly, Conic, Dragan, Mihaylov, Tzvetan, Sap, Annelies, Proost, Paul, Pierloot, Kristine, Van Meervelt, Luc, Parac-Vogt, Tatjana N
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Sprache:eng
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Zusammenfassung:The effect of the protein environment on the formation and stabilization of an elusive catalytically active polyoxometalate (POM) species, K6 [Hf(α2 -P2 W17 O61 )] (1), is reported. In the co-crystal of hen egg-white lysozyme (HEWL) with 1, the catalytically active monomeric species is observed, originating from the dimeric 1:2 POM form, while it is intrinsically unstable under physiological pH conditions. The protein-assisted dissociation of the dimeric POM was rationalized by means of DFT calculations. The dissociation process is unfavorable in bulk water, but becomes favorable in the protein-POM complex due to the low dielectric response at the protein surface. The crystal structure shows that the monomeric form is stabilized by electrostatic and water-mediated hydrogen bonding interactions with the protein. It interacts at three distinct sites, close to the aspartate-containing hydrolysis sites, demonstrating high selectivity towards peptide bonds containing this residue.
ISSN:0947-6539