Nmr studies on binary and ternary Pd(II) complexes formed by the growth-modulating tripeptide glycylhistidyllysine and nucleotides

Laussac, Jean‐Pierre; Pasdeloup, Maurice; Hadjiliadis, Nick

doi:10.1016/0162-0134(87)80066-1

Cited by 23 publications

(5 citation statements)

References 22 publications

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“…For example, Pd 2+ is square-planar when bound to Gly-Gly-His 49 and to Gly-His-Lys. 59 Here, 1 H NMR investigations have shown that Pd 2+ will also bind to HGGG, HGGGW and QPHGGGWGQ, forming 1 : 1 diamagnetic complexes in slow-exchange on the NMR timescale, between free and Pd 2+ bound peptide. The formation of the Pd 2+ complexes is slow reaching half maximal signal only after ∼3 hours.…”

Section: Discussionmentioning

confidence: 99%

A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

2006

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The prion protein (PrP C ) is a copper binding cell surface glycoprotein which when misfolded causes transmissible spongiform encephalopathies. The cooperative binding of Cu 2+ to an unstructured octarepeat sequence within PrP C causes profound folding of this region. The use of NMR to determine the solution structure of the octarepeat region of PrP with Cu 2+ bound has been hampered by the paramagnetic nature of the Cu 2+ ions. Using NMR we have investigated the binding of candidate diamagnetic replacement ions, to the octarepeat region of PrP. We show that Pd 2+ forms diamagnetic complexes with the peptides HGGG, HGGGW and QPHGGGWGQ with 1 : 1 stoichiometry. The 1 H NMR spectra indicate that these peptides are in slow-exchange between free and bound Pd 2+ on the chemical-shift time-scale. We demonstrate that the Pd-peptide complex forms slowly with a time taken to reach half-maximal signal of 3 hours. Other candidate metal ions, Ni 2+ , Pt 2+ and Au 3+ , were investigated but only the Pd 2+ complexes gave resolvable 1 H NMR spectra. We have determined the solution structure of the QPHGGGWGQ-Pd 1 : 1 complex using 71 NOE distance restraints. A backbone RMSD of 0.30 Å was observed over residues 3 to 7 in the final ensemble. The co-ordinating ligands consist of the histidine imidazole side chain Ne, the amide N of the second and third glycines with possibly H 2 O as the fourth ligand. The co-ordination geometry differs markedly from that of the HGGGW-Cu crystal structure. This survey of potential replacement metal ions to Cu 2+ provides insight into the metal specificity and co-ordination chemistry of the metal bound octarepeats.

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Section: Discussionmentioning

confidence: 99%

A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

2006

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“…Palladium(II) complexes with chelating ligands such as ethylenediamine (en) or diethylenetriamine (dien) have been extensively used to model the covalent interaction of analogous platinum(II) complexes with nucleobases, nucleosides, and nucleotides. The high reactivity exhibited by the palladium systems (up to 10 6 faster hydration kinetics) makes possible the study of binding equilibria which are sometimes difficult to determine for inert platinum(II) complexes. − …”

Section: Introductionmentioning

confidence: 99%

Covalent and Noncovalent Interactions for [Metal(dien)nucleobase]²⁺ Complexes with l-Tryptophan Derivatives: Formation of Palladium−Tryptophan Species by Nucleobase Substitution under Biologically Relevant Conditions

2006

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The interaction of the complexes [Pd(dien)(1-MeCyt)]2+ (2) and [Pd(dien)(9-EtGH)]2+ (3) with the amino acids L-tryptophan (Trp) and N-acetyltryptophan (N-AcTrp) was studied and compared with the previously studied platinum analogues [Pt(dien)(1-MeCyt)]2+ (4) and [Pt(dien)(9-EtGH)]2+ (5). Solid-state structures for 2 and 4 are reported. For the palladium complexes, the interaction is pH sensitive. Below pH 5, the noncovalent interaction with stacking between the aromatic amino acid residue and the metalated nucleobase was observed. Fluorescence quenching experiments indicated similar association constants for platinum and palladium derivatives 2-5. Unusual substitution of the model nucleobases 1-methylcytosine (1-MeCyt) and 9-ethylguanine (9-EtGH) by tryptophan was observed in the range of pH 5-11. The resulting species [Pd(dien)(Trp)]+ (6) and [Pd(dien)(N-AcTrp)]+ (7) were characterized using 1H NMR, 13C NMR, and ESI-MS spectroscopy with coordination indicated through the amino and deprotonated amido nitrogens, respectively. Complexes 6 and 7 were also obtained from a solution of [Pd(dien)Cl]+ (1) incubated with either Trp or N-AcTrp, respectively.

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“…[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.…”

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confidence: 99%

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

Ágoston¹,

Jankowska²,

Sóvágó³

1999

J. Chem. Soc., Dalton Trans.

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Palladium() complexes of peptides including Gly-Gly, Gly-Ala, Ala-Gly, Gly-Phe, Phe-Gly, triglycine, Gly-Gly-Ala and tetraglycine were studied by potentiometric and NMR spectroscopic methods. It was found that the reaction of free palladium() ion with dipeptides is almost complete below pH 2, therefore pH-metry can not be directly used for stability constant determinations. High excess of chloride ions (0.1 mol dm Ϫ3 ) was used to shift complex formation between [PdCl 4 ] 2Ϫ and peptides into the measurable pH range. The formation of the speciesϪ ) co-ordination was detected with all dipeptides in equimolar solutions. Bis complexes were formed in the presence of an excess of ligand, but their stoichiometry varied as a function of the amino acid sequences of the peptides. In the case of dipeptides with C-terminal Gly residues (X-Gly) the species [PdL 2 H -2 ] 2Ϫ with 4N co-ordination of two bidentate peptide molecules was formed by the physiological pH, while the stoichiometry of the bis complexes of dipeptides with non-co-ordinating side chains at the C termini (Gly-X) corresponds to [PdL 2 H Ϫ1 ] Ϫ containing both tridentate and monodentate peptide ligands. Equimolar solutions of palladium() and tripeptides are characterized by the formation of the species [PdLH Ϫ2 ] Ϫ with (NH 2 ,N Ϫ ,N Ϫ ,CO 2 Ϫ ) co-ordination, while [PdL 2 H Ϫ2 ] 2Ϫ containing two bidentate ligands is the main species in the presence of an excess of tripeptides.

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Nmr studies on binary and ternary Pd(II) complexes formed by the growth-modulating tripeptide glycylhistidyllysine and nucleotides

Cited by 23 publications

References 22 publications

A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

Covalent and Noncovalent Interactions for [Metal(dien)nucleobase]²⁺ Complexes with l-Tryptophan Derivatives: Formation of Palladium−Tryptophan Species by Nucleobase Substitution under Biologically Relevant Conditions

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

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Nmr studies on binary and ternary Pd(II) complexes formed by the growth-modulating tripeptide glycylhistidyllysine and nucleotides

Cited by 23 publications

References 22 publications

A survey of diamagnetic probes for copper2+binding to the prion protein.1H NMR solution structure of the palladium2+bound single octarepeat

A survey of diamagnetic probes for copper2+binding to the prion protein.1H NMR solution structure of the palladium2+bound single octarepeat

Covalent and Noncovalent Interactions for [Metal(dien)nucleobase]2+ Complexes with l-Tryptophan Derivatives: Formation of Palladium−Tryptophan Species by Nucleobase Substitution under Biologically Relevant Conditions

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

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A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

A survey of diamagnetic probes for copper²⁺binding to the prion protein.¹H NMR solution structure of the palladium²⁺bound single octarepeat

Covalent and Noncovalent Interactions for [Metal(dien)nucleobase]²⁺ Complexes with l-Tryptophan Derivatives: Formation of Palladium−Tryptophan Species by Nucleobase Substitution under Biologically Relevant Conditions