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Protein‐Assisted Formation and Stabilization of Catalytically Active Polyoxometalate Species
Author(s) -
Vandebroek Laurens,
De Zitter Elke,
Ly Hong Giang Thi,
Conić Dragan,
Mihaylov Tzvetan,
Sap Annelies,
Proost Paul,
Pierloot Kristine,
Van Meervelt Luc,
ParacVogt Tatja.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201802052
Subject(s) - polyoxometalate , chemistry , lysozyme , dissociation (chemistry) , hydrogen bond , monomer , hydrolase , crystallography , active site , residue (chemistry) , crystal structure , protein structure , stereochemistry , molecule , catalysis , enzyme , organic chemistry , biochemistry , polymer
The effect of the protein environment on the formation and stabilization of an elusive catalytically active polyoxometalate (POM) species, K 6 [Hf(α 2 ‐P 2 W 17 O 61 )] ( 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.