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Structural Characterization of the Complex between Hen Egg‐White Lysozyme and Zr IV ‐Substituted Keggin Polyoxometalate as Artificial Protease
Author(s) -
Sap Annelies,
De Zitter Elke,
Van Meervelt Luc,
ParacVogt Tatja.
Publication year - 2015
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.201501998
Subject(s) - polyoxometalate , lysozyme , monomer , crystallography , chemistry , keggin structure , hydrolysis , hydrolase , crystallization , stereochemistry , catalysis , organic chemistry , enzyme , polymer , biochemistry
Successful co‐crystallization of a noncovalent complex between hen egg‐white lysozyme (HEWL) and the monomeric Zr IV ‐substituted Keggin polyoxometalate (POM) (Zr1 K1), (Et 2 NH 2 ) 3 [Zr(PW 11 O 39 )] ( 1 ), has been achieved, and its single‐crystal X‐ray structure has been determined. The dimeric Zr IV ‐substituted Keggin‐type polyoxometalate (Zr1 K2), (Et 2 NH 2 ) 10 [Zr(PW 11 O 39 ) 2 ] ( 2 ), has been previously shown to exhibit remarkable selectivity towards HEWL hydrolysis. The reported X‐ray structure shows that the hydrolytically active Zr IV ‐substituted Keggin POM exists as a monomeric species. Prior to hydrolysis, this monomer interacts with HEWL in the vicinity of the previously identified cleavage sites found at Trp28‐Val29 and Asn44‐Arg45, through water‐mediated H‐bonding and electrostatic interactions. Three binding sites are observed at the interface of the negatively charged Keggin POM and the positively charged regions of HEWL at: 1) Gly16, Tyr20, and Arg21; 2) Asn44, Arg45, and Asn46; and 3) Arg128.