title: Structural Characterization of the Complex between Hen Egg-White Lysozyme and Zr(IV) -Substituted Keggin Polyoxometalate as Artificial Protease.
abstract: Successful co-crystallization of a noncovalent complex between hen egg-white lysozyme (HEWL) and the monomeric Zr(IV) -substituted Keggin polyoxometalate (POM) (Zr1 K1), (Et2 NH2)3 [Zr(PW11 O39)] (1), has been achieved, and its single-crystal X-ray structure has been determined. The dimeric Zr(IV) -substituted Keggin-type polyoxometalate (Zr1 K2), (Et2 NH2)10 [Zr(PW11 O39 )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.
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F box 2404, 3001 Leuven, Heverlee (Belgium).
authors.forename: Annelies
authors.initials: A
authors.lastname: Sap
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F box 2404, 3001 Leuven, Heverlee (Belgium).
authors.forename: Elke
authors.initials: E
authors.lastname: De Zitter
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F box 2404, 3001 Leuven, Heverlee (Belgium).
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
authors.affiliation: Department of Chemistry, KU Leuven, Celestijnenlaan 200F box 2404, 3001 Leuven, Heverlee (Belgium). tatjana.vogt@chem.kuleuven.be.
authors.forename: Tatjana N
authors.initials: TN
authors.lastname: Parac-Vogt
mesh_terms: D000818:Animals; D002645:Chickens; D018360:Crystallography, X-Ray; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D017973:Tungsten Compounds / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D009113:Muramidase; D017973:Tungsten Compounds; D015040:Zirconium; C102296:polyoxometalate I; D000099294:Polyoxometalates; C421864:hen egg lysozyme
keywords: co-crystallization; enzymes; interaction modes; lysozymes; polyoxometalates