Ternary palladium(II)–glycylmethionine-nucleobase complexes: solution studies and crystal structure of the 9-methylguanine compound

Abstract

With [Pt(Hamet)Cl 3 ] Ϫ a 6 ppm splitting of the 195 Pt resonance due to diastereomers has been detected at higher field strength.

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

“…An analogous cleavage of a Pt᎐N (en) bond has also been reported for the 1 : 1 [Pt(en)(H 2 O) 2 ] 2ϩ -gly-Hmet reaction system, leading to the formation of [Pt(Hen-κN)(gly-metκ 3 N,N Ј met ,S)] 2ϩ , in which the O-terminal side chain is once again involved in platinum co-ordination, 10 as has also recently been observed in a palladium() complex of gly-Hmet and 9-methylguanine. 28 However, in the case of gly-Hmet the high trans effect of the methionine sulfur in the intermediate product [Pt(en)(gly-met-κ 2 N Ј met ,S)] ϩ can be assumed to labilize the opposite Pt᎐N (en) bond, thereby favouring the adoption of a tridentate κ 3 N,N Ј met ,S binding pattern by the glycinecontaining dipeptide. A comparable reaction pathway for met-Hhis would require an intermediate with κ 2 N Ј his ,N 3 coordination, a species not detected in the range 3 < pH < 11 after incubation of the reaction mixture at 313 K for 14 d.…”

Potentiometric and NMR studies on palladium(II) complexes of oligoglycines and related ligands with non-co-ordinating side chains

“…[7][8][9][10][11][12][13][14][15][16][17] The most important findings in this field have been discussed in several reviews, [18][19][20] and it has been widely accepted that palladium() forms stable square planar, diamagnetic complexes with dipeptides, in which the terminal amino, deprotonated amide nitrogen and terminal carboxylate oxygen donor atoms are the metal binding sites. Of course, in the presence of strongly co-ordinating side chains like thioether of methionyl 21, 22 or imidazole of histidyl [23][24][25] residues the coordination of the carboxylate oxygen is replaced by the sulfur or nitrogen donor atoms, respectively, and it generally results in further increase of the thermodynamic stability of the corresponding peptide complexes. On the other hand, the co-ordination chemistry of simple dipeptides with nonco-ordinating side chains seems to be rather simple and unique.…”

Dipeptide L -Seryl- L -Methionine—Linear Dichroic IR and Theoretical Characterization

“…[1][2][3][4][5][6][7][8][9] In order to understand the in vivo manner and coordination mechanism of these ions with DNA, a systematic examination of their coordination ability with small peptides is necessary. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] The donor ability of the thioester groups in the methionine side chains is of particular interest. IR spectroscopy and nuclear magnetic resonance methods are powerful tools for studying these interactions, but the comparison of the spectroscopic properties of the pure ligands and their complexes requires knowledge of the corresponding spectroscopic characteristics.…”