Intramolecular competition between histidine and methionine side chains in reactions of dipeptides with [Pt(en)(H2O)2]2+ (en = H2NCH2CH2NH2)

Interaction of N-acetylmethionine with a non-C2-symmetrical platinum diamine complex

“…The 195 Pt NMR shifts of À2883 and À2868 ppm for the major and minor forms, respectively, were close to the range that has been observed for a PtN 2 SO coordination environment [7,9], suggesting either an S,O chelate or an S-coordinated N-AcMet with a D 2 O occupying the remaining coordination site. By acquiring a COSY spectrum at room temperature, we were able to assign the 1 H resonances of the N-AcMet ligand and the two ethyl groups of Et 2 en for both forms of the [Pt(Et 2 en)(N-AcMet-S,O)] + chelate (Table 3).…”

“…In the presence of a 1:1 ratio of platinum to methionine, the chelate [Pt(en)(N-AcMet-S,N)] was observed [8] in aqueous solution. Analogous S,N chelates have been observed in many studies involving platinum complexes coordinated to peptides [9,10].…”

Synthesis, spectroscopic analysis and structure deduction of gold(III), palladium(II) and platinum(II) complexes with the tripeptide glycyl-l-phenylalanyl-glycine

“…The fourth position in the Pt(II) ion is occupied by NH 3 + as terminal ligand (Scheme 3). These data correlate well with previous studies of the interaction of cis-Pt(NH 3 ) 2 Cl 2 with peptides [55][56][57][58][59]. In all the complexes, the observation of bands at frequencies above 3,500 cm -1 is assigned to water molecules in the outer coordination sphere of the complexes.…”

Characterisation of Cisplatin Binding Sites in Human Serum Proteins Using Hyphenated Multidimensional Liquid Chromatography and ESI Tandem Mass Spectrometry

“…Our MudPIT analyses have now demonstrated that Y150 (or Y148) and D375 (or E376) are characteristic binding sites for cisplatin in HSA, and that these, and possibly other O-donor sites, can exhibit a remarkable degree of kinetic stability. Because coordination by these residues is more rapid than for S-donor residues, [32][33][34] it is reasonable to assume that they play an important role in the initial transA C H T U N G T R E N N U N G port of the metallodrug. The relative thermodynamic weakness of PtÀO bonds means, however, that kO-coordinated cisplatin should be capable of slowly migrating to softer binding sites (e.g., DNA nucleobases) on reaching a target tumour cell.…”

“…[23] Previous studies of cisplatin binding to HSA [13][14][15][16] and other proteins [29][30][31] have emphasised the important role of the softer cysteine and methionine sulfur atoms as preferred targets, and our present investigation does, of course, confirm C34 and establish M329 and M548 as specific binding residues in HSA, and M256 in Trfe. O-donor atoms, however, are known to be kinetically preferred [32][33][34] as initial binding sites for cisplatin, and inspection of the 1 H, 15 N HSQC NMR spectrum taken for a cisplatin-HSA mixture (310 K, pH 6.4) after 2 h in the presence of added chloride (Figure 2 a in ref. [15]) confirms the presence of a number of intense cross peaks that are attributable to PtÀO binding trans to an ammine ligand (NH 3 ).…”