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Sigel A, Operschall BP, Sigel RKO, Sigel H. Metal ion complexes of nucleoside phosphorothioates reflecting the ambivalent properties of lead(ii). NEW J CHEM 2018. [DOI: 10.1039/c7nj04989g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The lead(ii)-lone pair leads to ambivalency: hemidirected (distorted, non-spherical) coordination spheres result from electronegative O-coordination and holodirected (symmetric, spherical) ones from less electronegative S-coordination.
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Affiliation(s)
- Astrid Sigel
- Department of Chemistry
- Inorganic Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
| | - Bert P. Operschall
- Department of Chemistry
- Inorganic Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
| | | | - Helmut Sigel
- Department of Chemistry
- Inorganic Chemistry
- University of Basel
- CH-4056 Basel
- Switzerland
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2
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Affiliation(s)
- Wenhu Zhou
- Xiangya
School of Pharmaceutical Sciences, Central South University, Changsha, Hunan 410013, China
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Runjhun Saran
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Juewen Liu
- Department
of Chemistry, Water Institute, and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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Sigel A, Operschall BP, Matera-Witkiewicz A, Świątek-Kozłowska J, Sigel H. Acid–base and metal ion-binding properties of thiopyrimidine derivatives. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Blindauer CA, Sigel A, Operschall BP, Griesser R, Holý A, Sigel H. Extent of intramolecular π stacks in aqueous solution in mixed-ligand copper(II) complexes formed by heteroaromatic amines and the anticancer and antivirally active 9-[2-(phosphonomethoxy)ethyl]guanine (PMEG). A comparison with related acyclic nucleotide analogues. Polyhedron 2016. [DOI: 10.1016/j.poly.2015.02.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Panteva MT, Giambaşu GM, York DM. Force Field for Mg(2+), Mn(2+), Zn(2+), and Cd(2+) Ions That Have Balanced Interactions with Nucleic Acids. J Phys Chem B 2015; 119:15460-70. [PMID: 26583536 DOI: 10.1021/acs.jpcb.5b10423] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Divalent metal ions are of fundamental importance to the function and folding of nucleic acids. Divalent metal ion-nucleic acid interactions are complex in nature and include both territorial and site specific binding. Commonly employed nonbonded divalent ion models, however, are often parametrized against bulk ion properties and are subsequently utilized in biomolecular simulations without considering any data related to interactions at specific nucleic acid sites. Previously, we assessed the ability of 17 different nonbonded Mg(2+) ion models to reproduce different properties of Mg(2+) in aqueous solution including radial distribution functions, solvation free energies, water exchange rates, and translational diffusion coefficients. In the present work, we depart from the recently developed 12-6-4 potential models for divalent metal ions developed by Li and Merz and tune the pairwise parameters for Mg(2+), Mn(2+), Zn(2+), and Cd(2+) binding dimethyl phosphate, adenosine, and guanosine in order to reproduce experimental site specific binding free energies derived from potentiometric pH titration data. We further apply these parameters to investigate a metal ion migration previously proposed to occur during the catalytic reaction of the hammerhead ribozyme. The new parameters are shown to be accurate and balanced for nucleic acid binding in comparison with available experimental data and provide an important tool for molecular dynamics and free energy simulations of nucleic acids where these ions may exhibit different binding modes.
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Affiliation(s)
- Maria T Panteva
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - George M Giambaşu
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
| | - Darrin M York
- Center for Integrative Proteomics Research, BioMaPS Institute and Department of Chemistry & Chemical Biology, Rutgers University , 174 Frelinghuysen Road, Piscataway, New Jersey 08854-8076, United States
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Salpin JY, Scuderi D. Structure of protonated thymidine characterized by infrared multiple photon dissociation and quantum calculations. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1898-1904. [PMID: 26411511 DOI: 10.1002/rcm.7296] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 07/23/2015] [Accepted: 07/29/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE Many fundamental studies are motivated by the probable relationship between the presence of rare enol tautomers of nucleobases and point mutation developing during nucleic acid replication. The evaluation of the tautomeric behaviour of nucleobases is therefore of fundamental importance. This can be probed in the gas phase by combining action spectroscopy and mass spectrometry. METHODS Experimental Infrared Multiple Photon Dissociation spectra in the fingerprint region of electrospray-generated and subsequently selected ions were recorded at the CLIO free electron laser (FEL) facility, by coupling the FEL to a quadrupole ion trap, and compared to calculated harmonic vibrational infrared spectra of the different low-lying isomers computed at the B3LYP/6-31++G(d,p) level. Relative energies were refined using the extended basis set 6-311++G(3df,2p). RESULTS The Density Functional Theory (DFT) study shows that, as for protonated thymine, the global energy minimum of protonated thymidine corresponds to an enol tautomer, whose infrared absorption spectrum is found to be in very good agreement with the experimental IRMPD spectrum. A very weak IRMPD signal observed at ~1780 cm(-1) is very likely the signature of an oxo tautomer. Consequently, as for thymine, protonated thymidine generated by electrospray corresponds to a mixture of at least two tautomeric forms. CONCLUSIONS Tautomerization can be characterized by IRMPD spectroscopy. Interestingly, the dominant enolic tautomeric form(s) presently observed cannot be directly generated from the most stable neutral tautomer of the thymine residue.
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Affiliation(s)
- Jean-Yves Salpin
- Université d'Evry Val d'Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, Boulevard François Mitterrand, 91025, Evry, France
- CNRS-UMR 8587
| | - Debora Scuderi
- Université Paris Sud Orsay, Laboratoire de Chimie Physique, Bâtiment 350, 91405, Orsay, France
- CNRS - UMR 8000
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Shukla MK, Leszczynski J. Tautomerism in nucleic acid bases and base pairs: a brief overview. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2013. [DOI: 10.1002/wcms.1145] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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Complex formation of cadmium with sugar residues, nucleobases, phosphates, nucleotides, and nucleic acids. Met Ions Life Sci 2013; 11:191-274. [PMID: 23430775 DOI: 10.1007/978-94-007-5179-8_8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cadmium(II), commonly classified as a relatively soft metal ion, prefers indeed aromatic-nitrogen sites (e.g., N7 of purines) over oxygen sites (like sugar-hydroxyl groups). However, matters are not that simple, though it is true that the affinity of Cd(2+) towards ribose-hydroxyl groups is very small; yet, a correct orientation brought about by a suitable primary binding site and a reduced solvent polarity, as it is expected to occur in a folded nucleic acid, may facilitate metal ion-hydroxyl group binding very effectively. Cd(2+) prefers the guanine(N7) over the adenine(N7), mainly because of the steric hindrance of the (C6)NH(2) group in the adenine residue. This Cd(2+)-(N7) interaction in a guanine moiety leads to a significant acidification of the (N1)H meaning that the deprotonation reaction occurs now in the physiological pH range. N3 of the cytosine residue, together with the neighboring (C2)O, is also a remarkable Cd(2+) binding site, though replacement of (C2)O by (C2)S enhances the affinity towards Cd(2+) dramatically, giving in addition rise to the deprotonation of the (C4)NH(2) group. The phosphodiester bridge is only a weak binding site but the affinity increases further from the mono- to the di- and the triphosphate. The same also holds for the corresponding nucleotides. Complex stability of the pyrimidine-nucleotides is solely determined by the coordination tendency of the phosphate group(s), whereas in the case of purine-nucleotides macrochelate formation takes place by the interaction of the phosphate-coordinated Cd(2+) with N7. The extents of the formation degrees of these chelates are summarized and the effect of a non-bridging sulfur atom in a thiophosphate group (versus a normal phosphate group) is considered. Mixed ligand complexes containing a nucleotide and a further mono- or bidentate ligand are covered and it is concluded that in these species N7 is released from the coordination sphere of Cd(2+). In the case that the other ligand contains an aromatic residue (e.g., 2,2'-bipyridine or the indole ring of tryptophanate) intramolecular stack formation takes place. With buffers like Tris or Bistris mixed ligand complexes are formed. Cd(2+) coordination to dinucleotides and to dinucleoside monophosphates provides some insights regarding the interaction between Cd(2+) and nucleic acids. Cd(2+) binding to oligonucleotides follows the principles of coordination to its units. The available crystal studies reveal that N7 of purines is the prominent binding site followed by phosphate oxygens and other heteroatoms in nucleic acids. Due to its high thiophilicity, Cd(2+) is regularly used in so-called thiorescue experiments, which lead to the identification of a direct involvement of divalent metal ions in ribozyme catalysis.
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Zhang S, Xu L, Dong J, Cheng P, Zhou Z, Fu J. Collision-induced dissociation of singly and doubly charged CuII–cytidine complexes in the gas phase: an experimental and computational study. RSC Adv 2012. [DOI: 10.1039/c2ra01293f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Salpin JY, Guillaumont S, Ortiz D, Tortajada J, Maître P. Direct evidence for tautomerization of the uracil moiety within the Pb2+/uridine-5'-monophosphate complex: a combined tandem mass spectrometry and IRMPD study. Inorg Chem 2011; 50:7769-78. [PMID: 21744847 DOI: 10.1021/ic200918q] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The structure of the [Pb(UMP)-H](+) (UMP = uridine-5'-monophosphate) complex was studied in the gas phase by combining electrospray ionization (ESI), tandem mass spectrometry, and mid-infrared multiple photon dissociation (IRMPD) spectroscopy. The results obtained show that Pb(2+) ions interact not only with the deprotonated phosphate group but also with a carbonyl group of the nucleobase moiety by folding of the mononucleotide, resulting in macrochelates that are not likely to be present in solution. Comparison between the IRMPD and DFT-computed spectra suggests that the ESI-generated complex likely corresponds to a mixture of several structures, and establishes the enolic tautomers as the most abundant species for the [Pb(UMP)-H](+) ion, while the very weak IRMPD signal observed at ∼1763 cm(-1) points to a minor population of oxo forms. Our data also suggest that losing the nucleobase residue under CID conditions does not necessarily mean a lack of interaction between the metal and the nucleobase moiety, as commonly reported in the literature for large oligonucleotides.
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Affiliation(s)
- Jean-Yves Salpin
- Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, Université d'Evry Val d'Essonn e, Bâtiment Maupertuis, Boulevard François Mitterrand, 91025 Evry, France.
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Sigel RKO, Sigel H. A stability concept for metal ion coordination to single-stranded nucleic acids and affinities of individual sites. Acc Chem Res 2010; 43:974-84. [PMID: 20235593 DOI: 10.1021/ar900197y] [Citation(s) in RCA: 171] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The three-dimensional architecture and function of nucleic acids strongly depend on the presence of metal ions, among other factors. Given the negative charge of the phosphate-sugar backbone, positively charged species, mostly metal ions, are necessary for compensation. However, these ions also allow and induce folding of complicated RNA structures. Furthermore, metal ions bind to specific sites, stabilizing local motifs and positioning themselves correctly to aid (or even enable) a catalytic mechanism, as, for example, in ribozymes. Many nucleic acids thereby exhibit large differences in folding and activity depending not only on the concentration but also on the kind of metal ion involved. As a consequence, understanding the role of metal ions in nucleic acids requires knowing not only the exact positioning and coordination sphere of each specifically bound metal ion but also its intrinsic site affinity. However, the quantification of metal ion affinities toward certain sites in a single-stranded (though folded) nucleic acid is a demanding task, and few experimental data exist. In this Account, we present a new tool for estimating the binding affinity of a given metal ion, based on its ligating sites within the nucleic acid. To this end, we have summarized the available affinity constants of Mg(2+), Ca(2+), Mn(2+), Cu(2+), Zn(2+), Cd(2+), and Pb(2+) for binding to nucleobase residues, as well as to mono- and dinucleotides. We have also estimated for these ions the stability constants for coordinating the phosphodiester bridge. In this way, stability increments for each ligand site are obtained, and a clear selectivity of the ligating atoms, as well as their discrimination by different metal ions, can thus be recognized. On the basis of these data, we propose a concept that allows one to estimate the intrinsic stabilities of nucleic acid-binding pockets for these metal ions. For example, the presence of a phosphate group has a much larger influence on the overall affinity of Mg(2+), Ca(2+), or Mn(2+) compared with, for example, that of Cd(2+) or Zn(2+). In the case of Cd(2+) and Zn(2+), the guanine N7 position is the strongest intrinsic binding site. By adding up the individual increments like building blocks, one derives an estimate not only for the overall stability of a given coordination sphere but also for the most stable complex if an excess of ligating atoms is available in a binding pocket saturating the coordination sphere of the metal ion. Hence, this empirical concept of adding up known intrinsic stabilities, like building blocks, to an estimated overall stability will help in understanding the accelerating or inhibiting effects of different metal ions in ribozymes and DNAzymes.
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Affiliation(s)
- Roland K. O. Sigel
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland,
| | - Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland
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Sigel H, Operschall BP, Griesser R. Xanthosine 5'-monophosphate (XMP). Acid-base and metal ion-binding properties of a chameleon-like nucleotide. Chem Soc Rev 2009; 38:2465-94. [PMID: 19623361 DOI: 10.1039/b902181g] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The four acidity constants of threefold protonated xanthosine 5'-monophosphate, H(3)(XMP)(+), reveal that in the physiological pH range around 7.5 (X - H x MP)(3-) strongly dominates and not XMP(2-) as commonly given in textbooks and often applied in research papers. Therefore, this nucleotide, which participates in many metabolic processes, should be addressed as xanthosinate 5'-monophosphate as is stated in this critical review. Micro acidity constant schemes allow quantification of intrinsic site basicities. In 9-methylxanthine nucleobase deprotonation occurs to more than 99% at (N3)H, whereas for xanthosine it is estimated that about 30% are (N1)H deprotonated and for (X - H x MP)(3-) it is suggested that (N1)H deprotonation is further favored, especially in macrochelates where the phosphate-coordinated M(2+) interacts with N7. The formation degree of these macrochelates in the (X - H x MP x M)(-) species of Co(2+), Ni(2+), Cu(2+), Zn(2+) or Cd(2+) amounts to 90% or more. In the monoprotonated (M x X - H x MP x H)(+/-) complexes, M(2+) is located at the N7/[(C6)O] unit as the primary binding site and it forms macrochelates with the P(O)(2)(OH)(-) group to about 65% for nearly all metal ions considered (i.e., including Ba(2+), Sr(2+), Ca(2+), Mg(2+)); this indicates outer-sphere binding to P(O)(2)(OH)(-). Finally, a new method quantifying the chelate effect is applied to the M(X - H x MP)(-) species, stabilities and structures of mixed-ligand complexes are considered, and the stability constants for several M(X - H x DP)(2-) and M(X - H x TP)(3-) complexes are estimated (112 references).
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Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland.
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Freisinger E, Griesser R, Lippert B, Moreno-Luque CF, Niclós-Gutiérrez J, Ochocki J, Operschall BP, Sigel H. Comparison of the surprising metal-ion-binding properties of 5- and 6-uracilmethylphosphonate (5Umpa2- and 6Umpa2-) in aqueous solution and crystal structures of the dimethyl and di(isopropyl) esters of H2(6Umpa). Chemistry 2009; 14:10036-46. [PMID: 18803205 DOI: 10.1002/chem.200800998] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
5- and 6-Uracilmethylphosphonate (5Umpa(2-) and 6Umpa(2-)) as acyclic nucleotide analogues are in the focus of anticancer and antiviral research. Connected metabolic reactions involve metal ions; therefore, we determined the stability constants of M(Umpa) complexes (M(2+)=Mg(2+), Ca(2+), Mn(2+), Co(2+), Cu(2+), Zn(2+), or Cd(2+)). However, the coordination chemistry of these Umpa species is also of interest in its own right, for example, the phosphonate-coordinated M(2+) interacts with (C4)O to form seven-membered chelates with 5Umpa(2-), thus leading to intramolecular equilibria between open (op) and closed (cl) isomers. No such interaction occurs with 6Umpa(2-). In both M(Umpa) series deprotonation of the uracil residue leads to the formation of M(Umpa-H)(-) complexes at higher pH values. Their stability was evaluated by taking into account the fact that the uracilate residue can bind metal ions to give M(2)(Umpa-H)(+) species. This has led to two further important insights: 1) In M(6Umpa-H)-cl the H(+) is released from (N1)H, giving rise to six-membered chelates (degrees of formation of ca. 90 to 99.9 % with Mn(2+), Co(2+), Cu(2+), Zn(2+), or Cd(2+)). 2) In M(5Umpa-H)$-cl the (N3)H is deprotonated, leading to a higher stability of the seven-membered chelates involving (C4)O (even Mg(2+) and Ca(2+) chelates are formed up to approximately 50 %). In both instances the M(Umpa-H)-op species led to the formation of M(2)(Umpa-H)(+) complexes that have one M(2+) at the phosphonate and one at the (N3)(-) (plus carbonyl) site; this proves that nucleotides can bind metal ions independently at the phosphate and the nucleobase residues. X-ray structural analyses of 6Umpa derivatives show that in diesters the phosphonate group is turned away from the uracil residue, whereas in H(2)(6Umpa) the orientation is such that upon deprotonation in aqueous solution a strong hydrogen bond is formed between (N1)H and PO(3) (2-); replacement of the hydro gen with M(2+) gives the M(6Umpa-H)-cl chelates mentioned.
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Affiliation(s)
- Eva Freisinger
- Institute of Inorganic Chemistry, University of Zürich, 8057 Zürich, Switzerland
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Grigoriev FV, Golovacheva AY, Romanov AN, Kondakova OA, Sulimov VB. The thermodynamic characteristics of formation of organic molecule complexes with the magnesium ion in water: The results of quantum-chemical modeling. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2009. [DOI: 10.1134/s0036024409040098] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Acid–base and metal ion binding properties of 2-thiocytidine in aqueous solution. J Biol Inorg Chem 2008; 13:663-74. [DOI: 10.1007/s00775-008-0351-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Accepted: 02/07/2008] [Indexed: 10/22/2022]
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Characterization of copper(II) interactions with sinefungin, a nucleoside antibiotic: combined potentiometric, spectroscopic and DFT studies. Bioinorg Chem Appl 2008:53521. [PMID: 18273386 PMCID: PMC2216065 DOI: 10.1155/2007/53521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Accepted: 11/09/2007] [Indexed: 11/25/2022] Open
Abstract
Interactions between sinefungin and copper(II) ions were investigated. Stoichiometry and stability constants of the
metal-free system and two mononuclear complexes present in solution were determined on the basis of potentiometric
data analysis. The results were compared to the Cu(II)-ornithine system due to structural similarities between both
molecules. Combined spectroscopic and theoretical studies allowed for determination of coordination pattern for
the Cu(II)-sinefungin complexes. At acidic pH, copper is bound in “glycine-like” coordination mode, identical with that
of ornithine. This involves α-amino group and the carboxyl oxygen. At higher pH, a “bis-complex” is formed by two
sinefungin molecules. The second ligand binds in equatorial position displacing two water molecules, what results
in the stable {2N,2O} coordination. Both axial positions are supposed to be occupied by N1 nitrogen donors of adenine
moiety, what is confirmed by DFT calculations. They interact indirectly with copper(II) through water molecules as the
result of dominant syn conformation of purine.
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Cheng P, Bohme DK. Gas-Phase Formation of Radical Cations of Monomers and Dimers of Guanosine by Collision-Induced Dissociation of Cu(II)−Guanosine Complexes. J Phys Chem B 2007; 111:11075-82. [PMID: 17715957 DOI: 10.1021/jp071933l] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An electrosprayed water/methanol solution of guanosine and Cu(NO3)2 was observed to give rise to gas-phase copper complexed ions of [CuLn]*2+, [CuL(MeOH)n]*2+, and [CuG n(NO3)]*+, as well as the ions [L]*+, [L+H]+, [G]*+, and [G+H]+ (L=guanosine, G=guanine). The Collision-Induced Dissociation (CID) of [CuL3]*2+ and [CuL(MeOH)n]*2+ (n=2, 3) generates guanosine radical cations [L]*+, while dimeric guanosine radical cations [L2]*+ are generated in the dissociation of [CuL4]*2+. Protonated guanosine [L+H]+ is one of the main products in the primary dissociation of [CuL2]*2+, while the dissociation of the higher-order [CuG2]*2+ produces the [G]*+ radical cation. The guanosine dimer radical cation, [L2]*+ presumably arises from the interaction of two guanosine molecules via proton and hydrogen bonding and is observed to dissociate into [L+H]+ and [L-H]* at low energies. We propose that the first two ligands bind strongly with Cu(II) through N7 and O6 to form a [CuL2]*2+ complex with a four-coordinated planar structure and that a third ligand binds loosely with copper to form [CuL3]*2+. Additional ligation observed in the formation of [CuLn]*2+ (n<or=6) ions is presumed to occur by hydrogen bonding. The ribose group of guanosine appears to play an important role in the stabilization of the doubly charged Cu-guanosine complex and in intraligand proton transfer upon CID. The molecular radical cations [L]*+ observed in the ESI-MS spectrum at low declustering potentials originate primarily from [CuL(MeOH)2,3]*2+ complexes which can dissociate more easily than [CuL3]*2+.
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Affiliation(s)
- Ping Cheng
- Department of Chemistry, Centre for Research in Mass Spectrometry and Centre for Research in Earth and Space Science, York University, Toronto, Ontario, Canada, M3J 1P3
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Biological recognition patterns implicated by the formation and stability of ternary metal ion complexes of low-molecular-weight formed with amino acid/peptides and nucleobases/nucleosides. Coord Chem Rev 2007. [DOI: 10.1016/j.ccr.2007.03.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Sigel H, Massoud SS, Song B, Griesser R, Knobloch B, Operschall BP. Acid-base and metal-ion-binding properties of xanthosine 5'-monophosphate (XMP) in aqueous solution: complex stabilities, isomeric equilibria, and extent of macrochelation. Chemistry 2007; 12:8106-22. [PMID: 16888737 DOI: 10.1002/chem.200600160] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The four acidity constants of threefold protonated xanthosine 5'-monophosphate, H3(XMP)+, reveal that at the physiological pH of 7.5 (XMP-H)(3-) strongly dominates (and not XMP(2-) as given in textbooks); this is in contrast to the related inosine (IMP(2-)) and guanosine 5'-monophosphate (GMP(2-)) and it means that XMP should better be named as xanthosinate 5'-monophosphate. In addition, evidence is provided for a tautomeric (XMP-HN1)(3-)/(XMP-HN3)(3-) equilibrium. The stability constants of the M(H;XMP)+ species were estimated and those of the M(XMP) and M(XMP-H)- complexes (M2+=Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+) measured potentiometrically in aqueous solution. The primary M2+ binding site in M(XMP) is (mostly) N7 of the monodeprotonated xanthine residue, the proton being at the phosphate group. The corresponding macrochelates involving P(O)2(OH)- (most likely outer-sphere) are formed to approximately 65% for nearly all M2+. In M(XMP-H)- the primary M2+ binding site is (mostly) the phosphate group; here the formation degree of the N7 macrochelates varies widely from close to zero for the alkaline earth ions, to approximately 50% for Mn2+, and approximately 90% or more for Co2+, Ni2+, Cu2+, Zn2+, and Cd2+. Because for (XMP-H)(3-) the micro stability constants quantifying the M2+ affinity of the xanthosinate and PO3(2-) residues are known, one may apply a recently developed quantification method for the chelate effect to the corresponding macrochelates; this chelate effect is close to zero for the alkaline earth ions and it amounts to about one log unit for Co2+, Ni2+, Cu2+. This method also allows calculation of the formation degrees of the monodentatally coordinated isomers; this information is of relevance for biological systems because it demonstrates how metal ions can switch from one site to another through macrochelate formation. These insights are meaningful for metal-ion-dependent reactions of XMP in metabolic pathways; previous mechanistic proposals based on XMP(2-) need revision.
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Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland.
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Freisinger E, Sigel RK. From nucleotides to ribozymes—A comparison of their metal ion binding properties. Coord Chem Rev 2007. [DOI: 10.1016/j.ccr.2007.03.008] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Odani A, Kozlowski H, Swiatek-Kozlowska J, Brasuń J, Operschall BP, Sigel H. Extent of metal ion-sulfur binding in complexes of thiouracil nucleosides and nucleotides in aqueous solution. J Inorg Biochem 2007; 101:727-35. [PMID: 17320183 DOI: 10.1016/j.jinorgbio.2006.12.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2006] [Revised: 12/17/2006] [Accepted: 12/22/2006] [Indexed: 10/23/2022]
Abstract
Previously published stability constants of several metal ion (M2+) complexes formed with thiouridines and their 5'-monophosphates, together with recently obtained log K(M(U))(M) versus pK(U)(H) plots for M2+ complexes of uridinate derivatives (U-) allowed now a quantitative evaluation of the effect that the exchange of a (C)O by a (C)S group has on the stability of the corresponding complexes. For example, the stability of the Ni2+, Cu2+ and Cd2+ complexes of 2-thiouridinate is increased by about 1.6, 2.3, and 1.3 log units, respectively, by the indicated exchange of groups. Similar results were obtained for other thiouridinates, including 4-thiouridinate. The structure of these complexes and the types of chelates formed (involving (N3)- and (C)S) are discussed. A recently advanced method for the quantification of the chelate effect allows now also an evaluation of several complexes of thiouridinate 5'-monophosphates. In most instances the thiouracilate coordination dominates the systems, allowing only the formation of small amounts of phosphate-bound isomers. Among the complexes studied only the one formed by Cu2+ with 2-thiouridinate 5'-monophosphate leads to significant amounts of the macrochelated isomer, which means that in this case Cu2+ is able to force the nucleotide from the anti to the syn conformation, allowing thus metal ion binding to both potential sites and this results in the formation of about 58% of the macrochelated isomer. The remaining 42% are species in which Cu2+ is overwhelmingly coordinated to the thiouracilate residue; Cu2+ binding to the phosphate group occurs in this case only in trace amounts.
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Affiliation(s)
- Akira Odani
- Department of Chemistry, Graduate School of Sciences, Nagoya University, Nagoya 464-8602, Japan.
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Sigel RKO, Pyle AM. Alternative Roles for Metal Ions in Enzyme Catalysis and the Implications for Ribozyme Chemistry. Chem Rev 2006; 107:97-113. [PMID: 17212472 DOI: 10.1021/cr0502605] [Citation(s) in RCA: 222] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Roland K O Sigel
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland.
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Knobloch B, Suliga D, Okruszek A, Sigel RKO. Acid-base and metal-ion binding properties of the RNA dinucleotide uridylyl-(5'-->3')-[5']uridylate (pUpU3-). Chemistry 2006; 11:4163-70. [PMID: 15861476 DOI: 10.1002/chem.200500013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
It is well known that Mg2+ and other divalent metal ions bind to the phosphate groups of nucleic acids. Subtle differences in the coordination properties of these metal ions to RNA, especially to ribozymes, determine whether they either promote or inhibit catalytic activity. The ability of metal ions to coordinate simultaneously with two neighboring phosphate groups is important for ribozyme structure and activity. However, such an interaction has not yet been quantified. Here, we have performed potentiometric pH titrations to determine the acidity constants of the protonated dinucleotide H2(pUpU)-, as well as the binding properties of pUpU3- towards Mg2+, Mn2+, Cd2+, Zn2+, and Pb2+. Whereas Mg2+, Mn2+, and Cd2+ only bind to the more basic 5'-terminal phosphate group, Pb2+, and to a certain extent also Zn2+, show a remarkably enhanced stability of the [M(pUpU)]- complex. This can be attributed to the formation of a macrochelate by bridging the two phosphate groups within this dinucleotide by these metal ions. Such a macrochelate is also possible in an oligonucleotide, because the basic structural units are the same, despite the difference in charge. The formation degrees of the macrochelated species of [Zn(pUpU)]- and [Pb(pUpU)]- amount to around 25 and 90 %, respectively. These findings are important in the context of ribozyme and DNAzyme catalysis, and explain, for example, why the leadzyme could be selected in the first place, and why this artificial ribozyme is inhibited by other divalent metal ions, such as Mg2+.
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Affiliation(s)
- Bernd Knobloch
- Institute of Inorganic Chemistry, University of Zürich, Switzerland
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Sigel H, Griesser R. Nucleoside 5'-triphosphates: self-association, acid-base, and metal ion-binding properties in solution. Chem Soc Rev 2005; 34:875-900. [PMID: 16172677 DOI: 10.1039/b505986k] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Adenosine 5'-triphosphate (ATP(4-)) and related nucleoside 5'-triphosphates (NTP(4-)) serve as substrates in the form of metal ion complexes in enzymic reactions taking part thus in central metabolic processes. With this in mind, the coordination chemistry of NTPs is critically reviewed and the conditions are defined for studies aiming to describe the properties of monomeric complexes because at higher concentrations (>1 mM) self-stacking may take place. The metal ion (M(2+)) complexes of purine-NTPs are more stable than those of pyrimidine-NTPs; this stability enhancement is attributed, in accord with NMR studies, to macrochelate formation of the phosphate-coordinated M(2+) with N7 of the purine residue and the formation degrees of the resulting isomeric complexes are listed. Furthermore, the formation of mixed-ligand complexes (including also those with buffer molecules), the effect of a reduced solvent polarity on complex stability and structure (giving rise to selectivity), the use of nucleotide analogues as antiviral agents, and the effect of metal ions on group transfer reactions are summarized.
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Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland.
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Affiliation(s)
- Roland K. O. Sigel
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland, Fax: +41‐44‐635‐6802
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Knobloch B, Linert W, Sigel H. Metal ion-binding properties of (N3)-deprotonated uridine, thymidine, and related pyrimidine nucleosides in aqueous solution. Proc Natl Acad Sci U S A 2005; 102:7459-64. [PMID: 15897459 PMCID: PMC1140430 DOI: 10.1073/pnas.0501446102] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2005] [Indexed: 11/18/2022] Open
Abstract
The acidity constants for (N3)H of the uridine-type ligands (U) 5-fluorouridine, 5-chloro-2'-deoxyuridine, uridine, and thymidine (2'-deoxy-5-methyluridine) and the stability constants of the M(U-H)(+) complexes for M(2+) = Mg(2+), Ca(2+), Sr(2+), Ba(2+), Mn(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), and Pb(2+) were measured (potentiometric pH titrations; aqueous solution; 25 degrees C; I = 0.1 M, NaNO(3)). Plots of logK(M(U-H))(M) vs. pK(U)(H) result in straight lines that are compared with previous plots for simple pyridine-type and o-amino(methyl)pyridine-type ligands as well as with the stabilities of the corresponding M(cytidine)(2+) complexes. The results indicate monodentate coordination to (N3)(-) in M(U-H)(+) for Co(2+) and Ni(2+). For the M(U-H)(+) species of Cd(2+), Zn(2+), or Cu(2+), increased stabilities imply that semichelates form, i.e., M(2+) is (N3)(-)-bound and coordinated water molecules form hydrogen bonds to (C2)O and (C4)O; these "double" semichelates are in equilibrium with "single" semichelates involving either (C2)O or (C4)O and possibly also with four-membered chelates for which M(2+) is innersphere-coordinated to (N3)(-) and a carbonyl oxygen. For the alkaline earth ions, semichelates dominate with the M(2+) outersphere bound to (N3)(-) and innersphere to one of the carbonyl oxygens. Mn(U-H)(+) is with its properties between those of Cd(2+) (which probably also hold for Pb(2+)) and the alkaline earth ions. In nucleic acids, M(2+)-C(O) interactions are expected, if support is provided by other primary binding sites. (N3)H may possibly be acidified via carbonyl-coordinated M(2+) to become a proton donor in the physiological pH range, at which direct (N3)(-) binding of M(2+) also seems possible.
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Affiliation(s)
- Bernd Knobloch
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland
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