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.
Peculiar features in the crystal structure of the adduct formed between cis-PtI2(NH3)2 and hen egg white lysozyme / Messori, L; Marzo, T; Gabbiani, C; Valdes, Aa; Quiroga, Ag; Merlino, Antonello. - In: INORGANIC CHEMISTRY. - ISSN 0020-1669. - 52:24(2013), pp. 13827-13829. [10.1021/ic402611m]
Peculiar features in the crystal structure of the adduct formed between cis-PtI2(NH3)2 and hen egg white lysozyme.
MERLINO, ANTONELLO
2013
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
