Noncovalent Complexes Formed between Metal‐Substituted Polyoxometalates and Hen Egg White Lysozyme

Abstract

Four Wells-Dawson type metal-substituted polyoxometalates (MSPs), 1:2 Zr IV -Wells-Dawson [Zr IV (α 2 -P 2 W 17 O 61 )] 8-(1), 1:1 Co II -Wells-Dawson [Co II (α 2 -P 2 W 17 O 61 )] 10-(2), 1:1 Ni II -Wells-Dawson [Ni II (α 2 -P 2 W 17 O 61 )] 10-(3) and 1:1 Cu II -Wells-Dawson [Cu II (α 2 -P 2 W 17 O 61 )] 10- (4), which differ in the nature of the imbedded metal ion, were examined in co-crystallization experiments with a protein Hen Egg White Lysozyme (HEWL). Single crystal X-ray structures of four noncovalent complexes between POMs and HEWL have been determined, and the influence of the type of substituted metal on the mode of POM binding to a [a]

Transition metal-substituted Keggin polyoxotungstates enabling covalent attachment to proteinase K upon co-crystallization

“…However, co-crystallizations of another transition-metal substituted POT of the Wells-Dawson archetype with lysozyme yielded only non-covalent complexes with the protein, and the substitution sites faced away from the protein surface with no preferential orientation. 33 In contrast, the Keggin POTs in this study surpassed mere electrostatic interactions with the protein surface.…”

Origin of Selectivity in Protein Hydrolysis by Zr(IV)-Containing Metal Oxides as Artificial Proteases

“…14,18,19 Moreover, close contacts of the guanidine groups of Arg45 and Arg68 with Zr-substituted POMs had been actually observed in crystal X-ray structures of noncovalent complexes. [15][16][17] Moving from simulations at site Asn44-Arg45 to the contiguous Arg45-Asn46 site, we only observed a significant stabilizing interaction between the ZrL anion and Arg45 that vanishes as the zirconium-oxygen distance shortens (Figure S18). As a result, the overall non-covalent interaction is significantly weaker for the Arg45-Asn46 site, becoming even slightly repulsive at coordination Zr-O distance (Figures 7D and 8).…”

Expanding the reactivity of inorganic clusters towards proteins: the interplay between the redox and hydrolytic activity of Ce(iv)-substituted polyoxometalates as artificial proteases

“…Firstly, unlike the hydrolytic reaction, the redox reaction does not need a direct interaction between the acceptor and the donor since the transfer of electrons can be mediated by the solvent; 48 secondly, MS-POMs usually bind proteins by pointing their hydrolytically active metal center towards the solvent, requiring an extra 'reorientation step' to turn the active metal center of MS-POMs towards the backbone of the protein. 32,49,50 Thirdly, Ce IV K 1 : 2 species needs to dissociate and form rst the hydrolytically active 1 : 1 species (Fig. 1) to be able to hydrolyze proteins, while this is not necessary for the redox reaction.…”