Conformation of (s-glutathionato)(2,2′

6′,2″-terpyridine)platinum(II) ion, [Pt(trpy)GS]+, determined from cross-relaxation effects in two-dimensional 1H NMR spectra. Importance of ligand-ligand hydrophobic interactions in metal-peptide complexes

Nenad Juranić, Vladimir Likić, Nenad M. Kostić, Slobodan I Macura

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18 Citations (Scopus)

Abstract

The tripeptide glutathione binds to the platinum(II) atom via the thiolato anion in the cysteine side chain. Conformation of the complex [Pt(trpy)GS]+ dissolved in a mixture of dimethylformamide-d7 and water at -15 °C is determined by a combination of molecular-mechanics calculations, molecular-dynamics calculations, and two-dimensional cross-relaxation 1H NMR spectroscopy. The viscous solvent and low temperature bring the complex into the spin-diffusion regime, so that cross-relaxation rates can accurately be determined. Interproton distances obtained from these rates serve as constraints in the minimization of molecular potential energy by standard methods. There are hydrophobic interactions between the glutamyl methylene groups in the glutathionato ligand and a terminal pyridine ring in the terpyridine ligand. This interaction excludes the most hydrophobic part of the glutathionato ligand from the polar solvent. Similar interactions may be responsible for the useful dependence of the UV-visible spectroscopic features of the [Pt(trpy)L]2+/+ chromophore, attached to the side chain L in proteins, on the environment of this side chain. Conformation of the glutathionato ligand in [Pt(trpy)GS]+ differs from the conformation of free glutathione in solution. This finding may be relevant to binding of glutathione to many enzymes that depend on it. This is an early, and promising, application of two-dimensional cross-relaxation NMR spectroscopy to stereochemistry of metal complexes.

Original languageEnglish (US)
Pages (from-to)938-944
Number of pages7
JournalInorganic Chemistry
Volume34
Issue number4
StatePublished - 1995

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cross relaxation
Platinum
glutathione
peptides
Conformations
platinum
Metals
Nuclear magnetic resonance
Ions
Ligands
Glutathione
Peptides
nuclear magnetic resonance
ligands
metals
Nuclear magnetic resonance spectroscopy
ions
interactions
Dimethylformamide
Stereochemistry

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

@article{b8a41d3ccaef47e7914dbf0abd0e6e2b,
title = "Conformation of (s-glutathionato)(2,2′: 6′,2″-terpyridine)platinum(II) ion, [Pt(trpy)GS]+, determined from cross-relaxation effects in two-dimensional 1H NMR spectra. Importance of ligand-ligand hydrophobic interactions in metal-peptide complexes",
abstract = "The tripeptide glutathione binds to the platinum(II) atom via the thiolato anion in the cysteine side chain. Conformation of the complex [Pt(trpy)GS]+ dissolved in a mixture of dimethylformamide-d7 and water at -15 °C is determined by a combination of molecular-mechanics calculations, molecular-dynamics calculations, and two-dimensional cross-relaxation 1H NMR spectroscopy. The viscous solvent and low temperature bring the complex into the spin-diffusion regime, so that cross-relaxation rates can accurately be determined. Interproton distances obtained from these rates serve as constraints in the minimization of molecular potential energy by standard methods. There are hydrophobic interactions between the glutamyl methylene groups in the glutathionato ligand and a terminal pyridine ring in the terpyridine ligand. This interaction excludes the most hydrophobic part of the glutathionato ligand from the polar solvent. Similar interactions may be responsible for the useful dependence of the UV-visible spectroscopic features of the [Pt(trpy)L]2+/+ chromophore, attached to the side chain L in proteins, on the environment of this side chain. Conformation of the glutathionato ligand in [Pt(trpy)GS]+ differs from the conformation of free glutathione in solution. This finding may be relevant to binding of glutathione to many enzymes that depend on it. This is an early, and promising, application of two-dimensional cross-relaxation NMR spectroscopy to stereochemistry of metal complexes.",
author = "Nenad Juranić and Vladimir Likić and Kostić, {Nenad M.} and Macura, {Slobodan I}",
year = "1995",
language = "English (US)",
volume = "34",
pages = "938--944",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
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TY - JOUR

T1 - Conformation of (s-glutathionato)(2,2′

T2 - 6′,2″-terpyridine)platinum(II) ion, [Pt(trpy)GS]+, determined from cross-relaxation effects in two-dimensional 1H NMR spectra. Importance of ligand-ligand hydrophobic interactions in metal-peptide complexes

AU - Juranić, Nenad

AU - Likić, Vladimir

AU - Kostić, Nenad M.

AU - Macura, Slobodan I

PY - 1995

Y1 - 1995

N2 - The tripeptide glutathione binds to the platinum(II) atom via the thiolato anion in the cysteine side chain. Conformation of the complex [Pt(trpy)GS]+ dissolved in a mixture of dimethylformamide-d7 and water at -15 °C is determined by a combination of molecular-mechanics calculations, molecular-dynamics calculations, and two-dimensional cross-relaxation 1H NMR spectroscopy. The viscous solvent and low temperature bring the complex into the spin-diffusion regime, so that cross-relaxation rates can accurately be determined. Interproton distances obtained from these rates serve as constraints in the minimization of molecular potential energy by standard methods. There are hydrophobic interactions between the glutamyl methylene groups in the glutathionato ligand and a terminal pyridine ring in the terpyridine ligand. This interaction excludes the most hydrophobic part of the glutathionato ligand from the polar solvent. Similar interactions may be responsible for the useful dependence of the UV-visible spectroscopic features of the [Pt(trpy)L]2+/+ chromophore, attached to the side chain L in proteins, on the environment of this side chain. Conformation of the glutathionato ligand in [Pt(trpy)GS]+ differs from the conformation of free glutathione in solution. This finding may be relevant to binding of glutathione to many enzymes that depend on it. This is an early, and promising, application of two-dimensional cross-relaxation NMR spectroscopy to stereochemistry of metal complexes.

AB - The tripeptide glutathione binds to the platinum(II) atom via the thiolato anion in the cysteine side chain. Conformation of the complex [Pt(trpy)GS]+ dissolved in a mixture of dimethylformamide-d7 and water at -15 °C is determined by a combination of molecular-mechanics calculations, molecular-dynamics calculations, and two-dimensional cross-relaxation 1H NMR spectroscopy. The viscous solvent and low temperature bring the complex into the spin-diffusion regime, so that cross-relaxation rates can accurately be determined. Interproton distances obtained from these rates serve as constraints in the minimization of molecular potential energy by standard methods. There are hydrophobic interactions between the glutamyl methylene groups in the glutathionato ligand and a terminal pyridine ring in the terpyridine ligand. This interaction excludes the most hydrophobic part of the glutathionato ligand from the polar solvent. Similar interactions may be responsible for the useful dependence of the UV-visible spectroscopic features of the [Pt(trpy)L]2+/+ chromophore, attached to the side chain L in proteins, on the environment of this side chain. Conformation of the glutathionato ligand in [Pt(trpy)GS]+ differs from the conformation of free glutathione in solution. This finding may be relevant to binding of glutathione to many enzymes that depend on it. This is an early, and promising, application of two-dimensional cross-relaxation NMR spectroscopy to stereochemistry of metal complexes.

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