Inorganic and Bioinorganic Solvent Exchange Mechanisms

Helm, Lothar; Merbach, André E.

doi:10.1021/cr030726o

Cited by 704 publications

(779 citation statements)

References 332 publications

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“…We previously tested various metal ions (Cr 3+ was not included) with DNA, where only Pt 2+ formed stable metallated DNA adduct. 40 The ligand exchange rate of Cr 3+ is about 100-fold slower than that of Pt 2+ , 16 Figure 5E). In a parallel experiment, a longer incubation time of 24 h was carried out, where the relative affinity still followed the same order, but the absolute affinity of each base increased ( Figure 5F).…”

Section: Resultsmentioning

confidence: 98%

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Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Zhou

Vazin

et al. 2016

Inorg. Chem.

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The interaction between chromium ions and DNA is of great interest in inorganic chemistry, toxicology, and analytical chemistry. Most previous studies focused on in situ reduction of Cr(VI), producing Cr 3+ for DNA binding. Recently, Cr 3+ was reported to activate the Ce13d DNAzyme for RNA cleavage. Herein, the Ce13d is used to study two types of Cr 3+ and DNA interactions. First, Cr 3+ binds to the DNA phosphate backbone weakly through reversible electrostatic interactions, which is weakened by adding competing inorganic phosphate. On the other hand, Cr 3+ coordinates with DNA nucleobases forming stable crosslinks that can survive denaturing gel electrophoresis condition. The binding of Cr 3+ to different nucleobases was further studied in terms of binding kinetic and affinity by exploiting FAM-labeled DNA homopolymers. Once binding takes place, the stable Cr 3+ /DNA complex cannot be dissociated by EDTA, attributable to the ultra-slow ligand exchange rate of Cr 3+ . The binding rate follows the order of G > C >T ≈ A. Finally, Cr 3+ gradually loses its DNA binding ability after storing at neutral or high pH, attributable hydrolysis. This hydrolysis can be reversed by lowering the pH.This work provides a deeper insight into the bioinorganic chemistry of Cr 3+ coordination with DNA, clarifies some inconsistency in the previous literature, and offers practically useful information for generating reproducible results.3

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Section: Resultsmentioning

confidence: 98%

“…16 Only a few studies touched on the interaction between Cr 3+ and nucleosides or DNA. Cr 3+ can bind to DNA through both phosphate backbone and nucleobases.…”

Section: Introductionmentioning

confidence: 99%

Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Zhou

Vazin

et al. 2016

Inorg. Chem.

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“…For the Fe(III)Fe(III) form of uteroferrin an upper limit of less than 1% of the activity of the heterovalent form has been determined [16], the release of the ultimate reaction product (phosphate) being proposed as the likely candidate for the rate-limiting step in the PAP-catalyzed reaction [1,18,25,40]. This hypothesis finds support in the relative water exchange rates of Fe(III) and Fe(II) (10 2 and 10 6 s -1 , respectively) [41][42][43]. The diferric model reported here is active and is, in some ways, a model for the oxidized PAP.…”

Section: Discussionmentioning

confidence: 94%

Phosphate ester cleavage promoted by a tetrameric iron(III) complex

et al. 2010

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The purple acid phosphatases (PAPs) are the only binuclear metallohydrolases where the necessity for a heterovalent active site [Fe(III)-M(II) (M is Fe, Zn or Mn)] for catalysis has been established. The paradigm for the construction of PAP biomimetics, both structural and functional, is that the ligands possess characteristics which mimic those of the donor sites of the metalloenzyme and permit discrimination between trivalent and divalent metal ions. The donor atom set of the ligand 2-((2-hydroxy-5-methyl-3-((pyridin-2-ylmethylamino)methyl)benzyl) (2-hydroxybenzyl)amino)acetic acid (H 3 HPBA) mimics that of the active site of PAP although the iron(III) complex of this ligand has been characterized as the tetramer [Fe 4 (HPBA) 2 (l-CH 3 COO) 2 (l-O)(l-OH)(OH 2 ) 2 ]ClO 4 Á5H 2 O. The phosphoesterase-like activity of the complex in 1:1 acetonitrile/water has now been investigated using the substrate 2,4-bis(dinitrophenyl)phosphate. The pH dependence of the catalytic rate revealed a non-symmetric bellshaped profile, with a finite but non-zero rate at high pH. Unlike the traditional approach usually employed to analyse these bell-shaped profiles, the approach used here involved incorporating additional species which contribute to the overall activity. Employing this approach, we show that the complex has a k cat of 1.6 (±0.2) 9 10 -3 s -1 , three kinetically relevant pK a values of 5.3, 6.2 and 8.4, with K M of 7.4 ± 0.6 mM. The kinetic parameters are similar to those reported for heterovalent PAP biomimetics. Additionally, it is observed that, unlike the enzyme, the oxidation state is not the determining factor for catalytic activity.

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“…44 Moreover, such information can help to understand the reasons for and mechanisms of typical ligand exchange and substitution processes in various solvent environments. In many cases the equilibrium between ligands, solvent molecules and metal ions can generate molecular structures and coordination numbers in solution that can differ significantly from those found in solid-state structures.…”

Section: Complex-formation On LI +mentioning

confidence: 99%

Elucidation of inorganic reaction mechanisms in ionic liquids: the important role of solvent donor and acceptor properties

Schmeisser

Eldik

2014

Dalton Trans.

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Inorganic and Bioinorganic Solvent Exchange Mechanisms

Cited by 704 publications

References 332 publications

Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Phosphate ester cleavage promoted by a tetrameric iron(III) complex

Elucidation of inorganic reaction mechanisms in ionic liquids: the important role of solvent donor and acceptor properties

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Inorganic and Bioinorganic Solvent Exchange Mechanisms

Cited by 704 publications

References 332 publications

Cr3+ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Cr3+ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Phosphate ester cleavage promoted by a tetrameric iron(III) complex

Elucidation of inorganic reaction mechanisms in ionic liquids: the important role of solvent donor and acceptor properties

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Product

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Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis

Cr³⁺ Binding to DNA Backbone Phosphate and Bases: Slow Ligand Exchange Rates and Metal Hydrolysis