title: Peculiar features in the crystal structure of the adduct formed between cis-PtI2(NH3)2 and hen egg white lysozyme.
abstract: The reactivity of cis-diamminediiodidoplatinum(II), cis-PtI2(NH3)2, the iodo analogue of cisplatin, with hen egg white lysozyme (HEWL) was investigated by electrospray ionization mass spectrometry and X-ray crystallography. Interestingly, the study compound forms a stable 1:1 protein adduct for which the crystal structure was solved at 1.99 Å resolution. In this adduct, the Pt(II) center, upon release of one ammonia ligand, selectively coordinates to the imidazole of His15. Both iodide ligands remain bound to platinum, with this being a highly peculiar and unexpected feature. Notably, two equivalent modes of Pt(II) binding are possible that differ only in the location of I atoms with respect to ND1 of His15. The structure of the adduct was compared with that of HEWL-cisplatin, previously described; differences are stressed and their important mechanistic implications discussed.
authors.affiliation: Department of Chemistry, University of Florence , Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Messori
authors.forename: Tiziano
authors.initials: T
authors.lastname: Marzo
authors.forename: Chiara
authors.initials: C
authors.lastname: Gabbiani
authors.forename: Amparo A
authors.initials: AA
authors.lastname: Valdes
authors.forename: Adoracion G
authors.initials: AG
authors.lastname: Quiroga
authors.forename: Antonello
authors.initials: A
authors.lastname: Merlino
mesh_terms: D002945:Cisplatin / Q000031:analogs & derivatives / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry* / Q000378:metabolism; D010984:Platinum / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D010984:Platinum; C421864:hen egg lysozyme; D009113:Muramidase; D002945:Cisplatin