Water exchange on metal ions: experiments and simulations

Helm, Lothar; Merbach, André E.

doi:10.1016/s0010-8545(99)90232-1

Cited by 490 publications

(502 citation statements)

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“…For example, it has been shown that metals in certain cases can be hydrogen-bond acceptors [23,24]. Moreover, the effect of metal ions on water structure has been thoroughly studied by both experimental and theoretical methods [25,26,27,28,29,30]. In particular, there have been several theoretical studies of solvated metal ions, noting that second-sphere water molecules have an increased hydrogen-bond strength [31,32].…”

Section: Introductionmentioning

confidence: 99%

How are hydrogen bonds modified by metal binding?

Husberg

Ryde

2013

J Biol Inorg Chem

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How are hydrogen bonds modified by metal binding?Husberg, Charlotte; Ryde, Ulf General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. AbstractWe have used density-functional theory calculations to investigate how the hydrogenbond strength is modified when a ligand is bound to a metal, using over 60 model systems involving six metals and eight ligands frequently encountered in metalloproteins. We study how the hydrogen-bond geometry and energy vary with the nature of metal, the oxidation state, the coordination number, the ligand involved in the hydrogen bond, other first-sphere ligands, and different hydrogen-bond probe molecules. The results show that in general, the hydrogen-bond strength is increased for neutral ligands and decreased for negatively charged ligands. The size of the effect is mainly determined by the net charge of the metal complex and all effects are typically decreased when the model is solvated. In water solution, the hydrogen-bond strength can increase by up to 37 kJ/mol for neutral ligands, and that of negatively charged ligands can both increase (for complexes with a negative net charge) or decrease (for positively charged complexes). If the net charge of the complex does not change, there is normally little difference between different metals or different types of complexes. The only exception is observed for sulphur-containing ligands (Met and Cys) and if the ligand is redox active (e.g. high-valent Fe-O complexes).Key Words: hydrogen bonds, metalloproteins, quantum-mechanical calculations, densityfunctional theory, dispersion correction, solvation. 2 IntroductionHydrogen bonds play an important role in all types of biochemical systems, strongly affecting catalysis, ligand binding, and enzyme function, for example [1]. They have been thoroughly studied by a variety of experimental and theoretical methods [2,3,4,5,6,7,8,9,10,11,12,13,14,15] so that the strengths of the common hydrogen bonds in biological systems are accurately known.However, it is well-known that metal sites affect the properties of bound ligands. For example, the pK a value of water in aqueous metal complexes is reduced from 15.7 for bulk water, to 12.8 for Ca 2+ and to 2.2 for Fe 3+ [16]. Therefore, it is also likely that metal ions also change the strength and structure of hydrogen bonds inv...

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Section: Introductionmentioning

confidence: 99%

How are hydrogen bonds modified by metal binding?

Husberg

Ryde

2013

J Biol Inorg Chem

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“…On the other extreme, metal complexes effective in cancer treatment are characterized by particularly slow kinetics that can be in the order of hours or days [240]. Mg 2+ is special with regard to its water-ligand exchange rate of ~2·10 5 s -1 being four orders of magnitude slower than that of most of the main group metal ions, but also significantly slower than many transition metal ions [241].…”

Section: Metal Ions Interact With Nucleic Acids On a Very Wide Rangementioning

confidence: 99%

Characterization of Metal Ion-Nucleic Acid Interactions in Solution

Pechlaner

Sigel

2011

Metal Ions in Life Sciences

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Metal ions are inextricably involved with nucleic acids due to their polyanionic nature. In order to understand the structure and function of RNAs and DNAs, one needs to have detailed pictures on the structural, thermodynamic, and kinetic properties of metal ion interactions with these biomacromolecules. In this review we first compile the physicochemical properties of metal ions found and used in combination with nucleic acids in solution. The main part then describes the various methods developed over the past decades to investigate metal ion binding by nucleic acids in solution. This includes for example hydrolytic and radical cleavage experiments, mutational approaches, as well as kinetic isotope effects. In addition, spectroscopic techniques like EPR, lanthanide(III) luminescence, IR and Raman as well as various NMR methods are summarized. Aside from gaining knowledge about the thermodynamic properties on the metal ion-nucleic acid interactions, especially NMR can be used to extract information on the kinetics of ligand exchange rates of the metal ions applied. The final section deals with the influence of anions, buffers, and the solvent permittivity on the binding equilibria between metal ions and nucleic acids. Little is known on some of these aspects, but it is clear that these three factors have a large influence on the interaction between metal ions and nucleic acids.

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“…Eventually, they concluded that the gradual decrease in CNs is continuous, not a discontinuous break. There have been some other papers of CN observations for Ln(III) [13][14][15]. Experimentally, it has been recognized that larger La-Nd ions have nine-fold coordination and smaller Ho-Lu ions do eight-fold one [1,4,12].…”

Section: Introductionmentioning

confidence: 99%