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Interactions of platinum(II) complexes with sulfur‐containing peptides studied by electrospray ionization mass spectrometry and tandem mass spectrometry
Author(s) -
Miao Ren,
Yang Gaosheng,
Miao Yi,
Mei Yuhua,
Hong Jin,
Zhao Chunmei,
Zhu Longgen
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1887
Subject(s) - chemistry , tandem mass spectrometry , electrospray ionization , mass spectrometry , ligand (biochemistry) , dissociation (chemistry) , collision induced dissociation , platinum , amide , denticity , medicinal chemistry , steric effects , chelation , stereochemistry , metal , inorganic chemistry , organic chemistry , chromatography , catalysis , biochemistry , receptor
Reactions of two platinum(II) complexes, cis ‐[Pt(NH 3 ) 2 (H 2 O) 2 ] 2+ (Pt1) and cis ‐[Pt(en)(H 2 O) 2 ] 2+ (Pt2), with several sulfur‐containing peptides, have been investigated by electrospray ionization mass spectrometry (ESI‐MS) and tandem mass spectrometry (MS/MS). The species produced in the reactions were detected with ESI‐MS, and MS/MS analysis was performed to probe structural information. Collision‐induced dissociation revealed different dissociation pathways for the main reaction products of the two platinum(II) complexes with the same peptides. The major difference is the prominent loss of ammonia ligand for complexes of Pt1 due to the strong trans effect of sulfur, whereas the loss of ethylenediamine (en) ligand from Pt2 complexes is less favored, reflecting the chelating effect of the bidentate ligand. Despite the differences in dissociation patterns, Pt1 and Pt2, in general, form structurally similar complexes with the same peptides. In the reactions with Met‐Arg‐Phe‐Ala they both produce a N,S‐chelate ring through the N‐terminal NH 2 and sulfur of the Met residue, and in the reactions with Ac‐Met‐Ala‐Ser they bind to the sulfur of Met and deprotonate an amide nitrogen upstream from the anchor site. Both of them are able to promote hydrolysis of the peptides. In reactions with glutathione they both form four‐membered Pt 2 S 2 rings and Pt‐S‐Pt bonding through the bridging thiolate ligand, although the reaction rate is much slower for Pt2 due to steric hindrance of the en ligand. Copyright © 2005 John Wiley & Sons, Ltd.