1
|
Equilibrium Studies on Pd(II)-Amine Complexes with Bio-Relevant Ligands in Reference to Their Antitumor Activity. Int J Mol Sci 2023; 24:ijms24054843. [PMID: 36902279 PMCID: PMC10003265 DOI: 10.3390/ijms24054843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/05/2023] [Accepted: 02/14/2023] [Indexed: 03/06/2023] Open
Abstract
This review article presents an overview of the equilibrium studies on Pd-amine complexes with bio-relevant ligands in reference to their antitumor activity. Pd(II) complexes with amines of different functional groups, were synthesized and characterized in many studies. The complex formation equilibria of Pd(amine)2+ complexes with amino acids, peptides, dicarboxylic acids and DNA constituents, were extensively investigated. Such systems may be considered as one of the models for the possible reactions occurring with antitumor drugs in biological systems. The stability of the formed complexes depends on the structural parameters of the amines and the bio-relevant ligands. The evaluated speciation curves can help to provide a pictorial presentation of the reactions in solutions of different pH values. The stability data of complexes with sulfur donor ligands compared with those of DNA constituents, can reveal information regarding the deactivation caused by sulfur donors. The formation equilibria of binuclear complexes of Pd(II) with DNA constituents was investigated to support the biological significance of this class of complexes. Most of the Pd(amine)2+ complexes investigated were studied in a low dielectric constant medium, resembling that of a biological medium. Investigations of the thermodynamic parameters reveal that the formation of the Pd(amine)2+ complex species is exothermic.
Collapse
|
2
|
Sigel A, Sigel H, Sigel RKO. Coordination Chemistry of Nucleotides and Antivirally Active Acyclic Nucleoside Phosphonates, including Mechanistic Considerations. Molecules 2022; 27:2625. [PMID: 35565975 PMCID: PMC9103026 DOI: 10.3390/molecules27092625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/08/2022] [Accepted: 04/10/2022] [Indexed: 11/17/2022] Open
Abstract
Considering that practically all reactions that involve nucleotides also involve metal ions, it is evident that the coordination chemistry of nucleotides and their derivatives is an essential corner stone of biological inorganic chemistry. Nucleotides are either directly or indirectly involved in all processes occurring in Nature. It is therefore no surprise that the constituents of nucleotides have been chemically altered-that is, at the nucleobase residue, the sugar moiety, and also at the phosphate group, often with the aim of discovering medically useful compounds. Among such derivatives are acyclic nucleoside phosphonates (ANPs), where the sugar moiety has been replaced by an aliphatic chain (often also containing an ether oxygen atom) and the phosphate group has been replaced by a phosphonate carrying a carbon-phosphorus bond to make the compounds less hydrolysis-sensitive. Several of these ANPs show antiviral activity, and some of them are nowadays used as drugs. The antiviral activity results from the incorporation of the ANPs into the growing nucleic acid chain-i.e., polymerases accept the ANPs as substrates, leading to chain termination because of the missing 3'-hydroxyl group. We have tried in this review to describe the coordination chemistry (mainly) of the adenine nucleotides AMP and ATP and whenever possible to compare it with that of the dianion of 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA2- = adenine(N9)-CH2-CH2-O-CH2-PO32) [or its diphosphate (PMEApp4-)] as a representative of the ANPs. Why is PMEApp4- a better substrate for polymerases than ATP4-? There are three reasons: (i) PMEA2- with its anti-like conformation (like AMP2-) fits well into the active site of the enzyme. (ii) The phosphonate group has an enhanced metal ion affinity because of its increased basicity. (iii) The ether oxygen forms a 5-membered chelate with the neighboring phosphonate and favors thus coordination at the Pα group. Research on ANPs containing a purine residue revealed that the kind and position of the substituent at C2 or C6 has a significant influence on the biological activity. For example, the shift of the (C6)NH2 group in PMEA to the C2 position leads to 9-[2-(phosphonomethoxy)ethyl]-2-aminopurine (PME2AP), an isomer with only a moderate antiviral activity. Removal of (C6)NH2 favors N7 coordination, e.g., of Cu2+, whereas the ether O atom binding of Cu2+ in PMEA facilitates N3 coordination via adjacent 5- and 7-membered chelates, giving rise to a Cu(PMEA)cl/O/N3 isomer. If the metal ions (M2+) are M(α,β)-M(γ)-coordinated at a triphosphate chain, transphosphorylation occurs (kinases, etc.), whereas metal ion binding in a M(α)-M(β,γ)-type fashion is relevant for polymerases. It may be noted that with diphosphorylated PMEA, (PMEApp4-), the M(α)-M(β,γ) binding is favored because of the formation of the 5-membered chelate involving the ether O atom (see above). The self-association tendency of purines leads to the formation of dimeric [M2(ATP)]2(OH)- stacks, which occur in low concentration and where one half of the molecule undergoes the dephosphorylation reaction and the other half stabilizes the structure-i.e., acts as the "enzyme" by bridging the two ATPs. In accord herewith, one may enhance the reaction rate by adding AMP2- to the [Cu2(ATP)]2(OH)- solution, as this leads to the formation of mixed stacked Cu3(ATP)(AMP)(OH)- species, in which AMP2- takes over the structuring role, while the other "half" of the molecule undergoes dephosphorylation. It may be added that Cu3(ATP)(PMEA) or better Cu3(ATP)(PMEA)(OH)- is even a more reactive species than Cu3(ATP)(AMP)(OH)-. - The matrix-assisted self-association and its significance for cell organelles with high ATP concentrations is summarized and discussed, as is, e.g., the effect of tryptophanate (Trp-), which leads to the formation of intramolecular stacks in M(ATP)(Trp)3- complexes (formation degree about 75%). Furthermore, it is well-known that in the active-site cavities of enzymes the dielectric constant, compared with bulk water, is reduced; therefore, we have summarized and discussed the effect of a change in solvent polarity on the stability and structure of binary and ternary complexes: Opposite effects on charged O sites and neutral N sites are observed, and this leads to interesting insights.
Collapse
Affiliation(s)
- Astrid Sigel
- Department of Chemistry, University of Basel, St. Johannsring 19, CH-4056 Basel, Switzerland;
| | - Helmut Sigel
- Department of Chemistry, University of Basel, St. Johannsring 19, CH-4056 Basel, Switzerland;
| | - Roland K. O. Sigel
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| |
Collapse
|
3
|
Ghiamati E, Sheikhani F, Farrokhi A. Potentiometric and Thermodynamic Studies of Some Metal-Cysteine Complexes. J CHIN CHEM SOC-TAIP 2017. [DOI: 10.1002/jccs.201700022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ebrahim Ghiamati
- Chemistry Department; University of Birjand, P.O. Box 414; Birjand Iran
| | - Faezeh Sheikhani
- Chemistry Department; University of Birjand, P.O. Box 414; Birjand Iran
| | - Alireza Farrokhi
- Chemistry Department; University of Birjand, P.O. Box 414; Birjand Iran
| |
Collapse
|
4
|
Khalaf-Alla PA, Shoukry MM, Jbarah AA, van Eldik R. Base hydrolysis of α-amino acid esters catalysed by [Pd(N-ethylethylenediamine)(H2O)2]2+. Kinetic study and DFT calculations. Inorganica Chim Acta 2017. [DOI: 10.1016/j.ica.2017.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
5
|
Mixed-ligand complex formation of tenoxicam drug with some transition metal ions in presence of valine: Synthesis, characterization, molecular docking, potentiometric and evaluation of the humeral immune response of calves. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.09.065] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
6
|
Nageswara Rao C, Srinu B, Gowri Kumari V, Sailaja BBV. Computer-augmented modeling studies of Pb(II) and Cd(II) complexes with maleic acid in ethylene glycol–water mixture. CHEMICAL SPECIATION AND BIOAVAILABILITY 2016. [DOI: 10.1080/09542299.2015.1109479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ch. Nageswara Rao
- Department of Inorganic & Analytical Chemistry, Andhra University, Visakhapatnam, India
| | - Bogi Srinu
- Department of Inorganic & Analytical Chemistry, Andhra University, Visakhapatnam, India
| | - V. Gowri Kumari
- Department of Inorganic & Analytical Chemistry, Andhra University, Visakhapatnam, India
| | - B. B. V. Sailaja
- Department of Inorganic & Analytical Chemistry, Andhra University, Visakhapatnam, India
| |
Collapse
|
7
|
Kim JC. Molecular Interactions of a, e-cis-1,4-cyclohexanedicarboxylate (chdc) and e, e-trans-1,4-chdc Ions toward Macrocyclic Zinc(II) Complexes. B KOREAN CHEM SOC 2015. [DOI: 10.1002/bkcs.10375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Ju Chang Kim
- Department of Chemistry; Pukyong National University; Busan 608-737 Korea
| |
Collapse
|
8
|
Lüth MS, Freisinger E, Kampf G, Garijo Anorbe M, Griesser R, Operschall BP, Sigel H, Lippert B. Connectivity patterns and rotamer states of nucleobases determine acid-base properties of metalated purine quartets. J Inorg Biochem 2015; 148:93-104. [PMID: 25773716 DOI: 10.1016/j.jinorgbio.2015.02.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 10/24/2022]
Abstract
Potentiometric pH titrations and pD dependent (1)H NMR spectroscopy have been applied to study the acidification of the exocyclic amino group of adenine (A) model nucleobases (N9 position blocked by alkyl groups) when carrying trans-a2Pt(II) (with a=NH3 or CH3NH2) entities both at N1 and N7 positions. As demonstrated, in trinuclear complexes containing central A-Pt-A units, it depends on the connectivity pattern of the adenine bases (N7/N7 or N1/N1) and their rotamer states (head-head or head-tail), how large the acidifying effect is. Specifically, a series of trinuclear complexes with (A-N7)-Pt-(N7-A) and (A-N1)-Pt-(N1-A) cross-linking patterns and terminal 9-alkylguanine ligands (9MeGH, 9EtGH) have been analyzed in this respect, and it is shown that, for example, the 9MeA ligands in trans-,trans-,trans-[Pt(NH3)2(N7-9MeA-N1)2{Pt(NH3)2(9EtGH-N7)}2](ClO4)6·6H2O (4a) and trans-,trans-,trans-[Pt(NH3)2(N7-9EtA-N1)2{Pt(CH3NH2)2(9-MeGH-N7)}2](ClO4)6·3H2O (4b) are more acidic, by ca. 1.3 units (first pKa), than the linkage isomer trans-,trans-,trans-[Pt(CH3NH2)2(N1-9MeA-N7)2{Pt(NH3)2(9MeGH-N7)}2](NO3)6·6.25H2O (1b). Overall, acidifications in these types of complexes amount to 7-9 units, bringing the pKa values of such adenine ligands in the best case close to the physiological pH range. Comparison with pKa values of related trinuclear Pt(II) complexes having different co-ligands at the Pt ions, confirms this picture and supports our earlier proposal that the close proximity of the exocyclic amino groups in a head-head arrangement of (A-N7)-Pt-(N7-A), and the stabilization of the resulting N6H(-)⋯H2N6 unit, is key to this difference.
Collapse
Affiliation(s)
- Marc Sven Lüth
- Fakultät Chemie und Chemische Biologie (CCB), Technische Universität, Dortmund 44221 Dortmund, Germany; Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Eva Freisinger
- Department of Chemistry, University of Zürich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
| | - Gunnar Kampf
- Fakultät Chemie und Chemische Biologie (CCB), Technische Universität, Dortmund 44221 Dortmund, Germany; Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Marta Garijo Anorbe
- Fakultät Chemie und Chemische Biologie (CCB), Technische Universität, Dortmund 44221 Dortmund, Germany
| | - Rolf Griesser
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Bert P Operschall
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland
| | - Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland.
| | - Bernhard Lippert
- Fakultät Chemie und Chemische Biologie (CCB), Technische Universität, Dortmund 44221 Dortmund, Germany.
| |
Collapse
|
9
|
Nakagawa Y, Sehata S, Fujii S, Yamamoto H, Tsuda A, Koumoto K. Mechanistic study on the facilitation of enzymatic hydrolysis by α-glucosidase in the presence of betaine-type metabolite analogs. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.06.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
EL-Gahami MA, Al-Bogami AS, Albishri HM. Medium effect on the dimethyltin(IV) complexes of 2-(N-morpholino) ethanesulfonic and 3-(N-morpholino) propanesulfonic acid. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
11
|
Thermodynamic investigation of the binary and ternary complexes involving 1-aminocyclopropane carboxylic acid with reference to plant hormone. OPEN CHEM 2014. [DOI: 10.2478/s11532-013-0374-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractComplex formation equilibria of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) with metal ions Cu2+, Ni2+, Co2+, Zn2+, Mn2+ and Fe2+ were investigated. ACC forms 1:1 and 1:2 complexes in addition to the hydrolysed form of the 1:1 complex, except in the case of Mn2+ and Fe2+, where the hydrolysed complex is not formed. BIMP forms 1:1 and 1:2 complexes in addition to the hydrolsed form of the 1:1 complex in the case of Mn2+ and Cu2+, however the hydrolysed complex is not detected for Ni2+, Co2+, Zn2+ and Fe2+. The concentration distribution diagrams of the complexes were determined. The Fe2+-complex with BIMP is exothermic and the thermodynamic parameters were calculated. The effect of organic solvent on the acid dissociation constants of 1-aminocyclopropane carboxylic acid (ACC) and 3,3-bis(1-methylimidazol-2-yl) propionic acid (BIMP) and the formation constants of Fe2+ complexes were investigated. Fe2+ forms a mixed-ligand complex with ACC and BIMP with stoichiometric coefficients 1:1:1. The formation constant was determined. The ternary complex is enhanced by back donation from the negatively charged 1-aminocyclopropane carboxylate to the π-system of BIMP. From the concentration distribution diagram, the ternary complex prevails in the physiological pH range.
Collapse
|
12
|
Equilibrium Studies of Dibutyltin(IV)-Zwitterionic Buffer Complexation. J SOLUTION CHEM 2013; 42:2012-2024. [PMID: 24273357 PMCID: PMC3825530 DOI: 10.1007/s10953-013-0088-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 06/01/2013] [Indexed: 11/11/2022]
Abstract
Equilibrium studies in aqueous solution are reported for dibutyltin(IV) (DBT) complexes of the zwitterionic buffers “Good’s buffers” Mes and Mops. Stoichiometric and formation constants of the complexes formed were determined at different temperatures and ionic strength 0.1 mol·L−1 NaNO3. The results show that the best fit of the titration curves were obtained when the complexes ML, MLH−1, MLH−2 and MLH−3 were considered beside the hydrolysis product of the dibutyltin(IV) cation. The thermodynamic parameters ΔHo, ΔSo and ΔGo calculated from the temperature dependence of the formation constant of the dibutyltin(IV) complexes with 2-(N-morpholino)ethanesulfonic acid (Mes) and 3-(N-mor-pholino)-propanesulfonic acid (Mops) were investigated. The effect of dioxane as a solvent on the formation constants of DBT–Mes and DBT–Mops complexes decrease linearly with the increase of dioxane proportion in the medium. The concentration distribution of the various complexes species was evaluated as a function of pH.
Collapse
|
13
|
Equilibrium studies of thallium(I) complexes with cytidine 5′-monophosphate in different aqueous solutions of methanol. J Mol Liq 2013. [DOI: 10.1016/j.molliq.2013.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
14
|
Swaroopa Rani R, Chandra Leela A, Nageswara Rao G. Effect of Dielectric Constant on Protonation Equilibria of l-Aspartic Acid and Ethylenediamine in 1,2-Propanediol–water Mixtures. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2012. [DOI: 10.1007/s40010-012-0047-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
15
|
Padmaja N, Rao GN. Speciation Studies of Pb(II), Cd(II) and Hg(II) Complexes of 1,10-Phenanthroline in 1,4 Dioxan–Water Mixtures. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2012. [DOI: 10.1007/s40010-012-0024-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
16
|
Shoukry MM, Hassouna M, Mahmoud R. Palladium(II) complex taken as a model of an antitumour agent: Synthesis and equilibrium investigation involving biologically relevant ligands. CR CHIM 2012. [DOI: 10.1016/j.crci.2011.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
17
|
Kinetics and Mechanism for Hydrolysis of α-Amino Acid Esters in Mixed Ligand Complexes with Zn(II)–Nitrilo-tris(methyl phosphonic Acid). J SOLUTION CHEM 2012. [DOI: 10.1007/s10953-012-9799-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Tegoni M, Remelli M. Metallacrowns of copper(II) and aminohydroxamates: Thermodynamics of self assembly and host–guest equilibria. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.06.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
19
|
Abstract
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.
Collapse
Affiliation(s)
- Maria Pechlaner
- Institute of Inorganic Chemistry, University of Zürich, Zürich, Switzerland
| | | |
Collapse
|
20
|
Hassan SS, Shoukry MM, van Eldik R. Thermodynamics of the interaction of ruthenium(iii) polyaminecarboxylate complexes with bio-relevant ligands. Deactivation of the complexes as NO scavengers by thiol ligands. Dalton Trans 2012; 41:13447-53. [DOI: 10.1039/c2dt31730c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
21
|
Creus M, Ward TR. Design and Evolution of Artificial Metalloenzymes: Biomimetic Aspects. PROGRESS IN INORGANIC CHEMISTRY 2011. [DOI: 10.1002/9781118148235.ch4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
22
|
El-Sherif AA. Synthesis and characterization of some potential antitumor palladium(II) complexes of 2-aminomethylbenzimidazole and amino acids. J COORD CHEM 2011. [DOI: 10.1080/00958972.2011.587004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ahmed A. El-Sherif
- a Faculty of Science, Department of Chemistry , Cairo University , Giza, Egypt
| |
Collapse
|
23
|
Al-Sogair FM, Operschall BP, Sigel A, Sigel H, Schnabl J, Sigel RKO. Probing the metal-ion-binding strength of the hydroxyl group. Chem Rev 2011; 111:4964-5003. [PMID: 21595429 DOI: 10.1021/cr100415s] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fawzia M Al-Sogair
- Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | | | | | | | | | | |
Collapse
|
24
|
El-Sherif AA. Coordination properties of bidentate (N,O) and tridentate (N,O,O) heterocyclic alcohols with dimethyltin(IV). J COORD CHEM 2011. [DOI: 10.1080/00958972.2011.565755] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ahmed A. El-Sherif
- a Department of Chemistry , Faculty of Science, Cairo University , Cairo, Egypt
| |
Collapse
|
25
|
Complex formation reactions of palladium(II)-1,3-diaminopropane with various biologically relevant ligands. Kinetics of hydrolysis of glycine methyl ester through complex formation. OPEN CHEM 2010. [DOI: 10.2478/s11532-010-0057-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AbstractThe interaction of [Pd(DAP)(H2O)2]2+ (DAP = 1,3-diaminopropane) with some selected bio-relevant ligands, containing different functional groups, were investigated. The ligands used are dicarboxylic acids, amino acids, peptides and DNA constituents. Stoichiometry and stability constants of the complexes formed are reported at 25°C and 0.1 M ionic strength. The results show the formation of 1:1 complexes with amino acids and dicarboxylic acids. The effect of chelate ring size of the dicarboxylic acid complexes on their stability constants is examined. Peptides form both 1:1 complexes and the corresponding deprotonated amide species. DNA constituents form 1:1 and 1:2 complexes. The effect of dioxane on the acid dissociation constants of CBDCA and the formation constant of its complex with Pd(DAP)2+ was reported. The kinetics of hydrolysis of glycine methyl ester bound to [Pd(DAP)(H2O)2]2+ was studied at 25°C and 0.1M ionic strength.
Collapse
|
26
|
Kinetics of base hydrolysis of α-amino acid esters catalyzed by palladium(II) piperazine complex. OPEN CHEM 2010. [DOI: 10.2478/s11532-010-0047-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractThe kinetics of base hydrolysis of glycine, histidine, and methionine methyl esters in the presence of [Pd(pip)(H2O)2]2+ complex, where pip is piperazine, is studied in aqueous solutions, at T = 25°C, and I = 0.1 mol dm−3. The rate of ester hydrolysis for glycine methyl ester is studied at different temperature and dioxane/water solutions of different compositions. The kinetic data are fit under the assumption that the hydrolysis proceeds in one step. The activation parameters for the base hydrolysis of the complexes are evaluated
Collapse
|
27
|
Shoukry MM, Al-Najjar AA, Hosny WM, Abdel Hadi AK, Mahgoub AA, Khalf Alla PA. Kinetics of base hydrolysis of α-amino acid esters catalyzed by [Pd(Et 4en)(H 2O) 2] 2+. J COORD CHEM 2010. [DOI: 10.1080/00958972.2010.506611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Mohamed M. Shoukry
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| | - Abdul Aziz Al-Najjar
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| | - Wafaa M. Hosny
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| | - Afkar K. Abdel Hadi
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| | - Afaf A. Mahgoub
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| | - Perihan A. Khalf Alla
- a Department of Chemistry, Faculty of Science , Cairo University , 12613 Al Jizah, Egypt
| |
Collapse
|
28
|
Shehata MR, Shoukry MM, Abdel-Shakour FH, van Eldik R. Equilibrium Studies on Complex-Formation Reactions of Pd[(2-(2-aminoethyl)pyridine)(H2O)2]2+with Ligands of Biological Significance and Displacement Reactions of DNA Constituents. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200900352] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
29
|
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: 25] [Impact Index Per Article: 1.6] [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).
Collapse
Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland.
| | | | | |
Collapse
|
30
|
Tao P, Fisher JF, Mobashery S, Bernhard Schlegel H. DFT studies of the ring-opening mechanism of SB-3CT, a potent inhibitor of matrix metalloproteinase 2. Org Lett 2009; 11:2559-62. [PMID: 19445474 PMCID: PMC2821186 DOI: 10.1021/ol9008393] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
SB-3CT is a 2-[(arylsulfonyl)methyl]thiirane that achieves potent inhibition, by a thiirane-opening mechanism, of the MMP2 and MMP9 zinc metalloproteases. The deprotonation mechanism for thiirane opening of SB-3CT and for the opening of its oxirane analogue, both relevant to the inhibition of MMP2, was investigated computationally using the acetate anion as the Brønsted base and in methanol and acetonitrile as solvents. The activation barriers for the reaction show a significant stereoelectronic effect. The lowest energy paths have the breaking C-H bond gauche to both sulfone oxygens and with this C-H bond anti to the breaking C-S bond of the thiirane. The calculated primary isotope effect agrees with experimental data.
Collapse
Affiliation(s)
- Peng Tao
- Department of Chemistry, Wayne State University, 5101 Cass Ave Detroit, Michigan 48202
| | - Jed F. Fisher
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, 5101 Cass Ave Detroit, Michigan 48202
| |
Collapse
|
31
|
Bastian M, Sigel H. Stability and Structure of Binary and Ternary Metal Ion Complexes of Orotidinate 5′-Monophosphate (OMP3-) in Aqueous Solution. J COORD CHEM 2009. [DOI: 10.1080/00958979109408247] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Matthias Bastian
- a Institute of Inorganic Chemistry, University of Basel , Spitalstrasse 51, CH-4056 , Basel , Switzerland
| | - Helmut Sigel
- a Institute of Inorganic Chemistry, University of Basel , Spitalstrasse 51, CH-4056 , Basel , Switzerland
| |
Collapse
|
32
|
Furler M, Knobloch B, Sigel RK. Influence of decreased solvent permittivity on the structure and magnesium(II)-binding properties of the catalytic domain 5 of a group II intron ribozyme. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2008.03.095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
33
|
Tegoni M, Tropiano M, Marchiò L. Thermodynamics of binding of carboxylates to amphiphilic Eu3+/Cu2+ metallacrown. Dalton Trans 2009:6705-8. [DOI: 10.1039/b911512a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
34
|
Operschall BP, Bianchi EM, Griesser R, Sigel H. Influence of decreasing solvent polarity (1,4-dioxane/water mixtures) on the stability and structure of complexes formed by copper(II), 2,2′-bipyridine or 1,10-phenanthroline and guanosine 5′-diphosphate: evaluation of isomeric equilibria. J COORD CHEM 2008. [DOI: 10.1080/00958970802474888] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Bert P. Operschall
- a Department of Chemistry, Inorganic Chemistry , University of Basel , Spitalstrasse 51, CH-4056 Basel, Switzerland
| | - Emanuela M. Bianchi
- a Department of Chemistry, Inorganic Chemistry , University of Basel , Spitalstrasse 51, CH-4056 Basel, Switzerland
| | - Rolf Griesser
- a Department of Chemistry, Inorganic Chemistry , University of Basel , Spitalstrasse 51, CH-4056 Basel, Switzerland
| | - Helmut Sigel
- a Department of Chemistry, Inorganic Chemistry , University of Basel , Spitalstrasse 51, CH-4056 Basel, Switzerland
| |
Collapse
|
35
|
Shoukry AA, Shoukry MM. Coordination properties of hydralazine Schiff base Synthesis and equilibrium studies of some metal ion complexes. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 70:686-691. [PMID: 17950027 DOI: 10.1016/j.saa.2007.08.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 08/24/2007] [Accepted: 08/27/2007] [Indexed: 05/25/2023]
Abstract
In the present study, a new ligand is prepared by condensation of hydralazine (1-Hydralazinophthalazine) with 2-butanon-3-oxime. The acid-base equilibria of the schiff-base and the complex formation equilibria with the metal ions as Cu(II), Ni(II), Co(II), Cd(II), Mn(II) and Zn(II) are investigated potentiometrically. The stability constants of the complexes are determined and the concentration distribution diagrams of the complexes are evaluated. The effect of metal ion properties as atomic number, ionic radius, electronegativity and ionization potential are investigated. The isolated solid complexes are characterized by conventional chemical and physical methods. The potential coordination sites are assigned using the i.r. and (1)H NMR spectra. The structures of the isolated solid complexes are proposed on the basis of the spectral and magnetic studies.
Collapse
Affiliation(s)
- Azza A Shoukry
- Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt
| | | |
Collapse
|
36
|
Al Alousi ASH, Shehata MR, Shoukry MM, Hassan SA, Mahmoud N. Coordination properties of dehydroacetic acid – binary and ternary complexes. J COORD CHEM 2008. [DOI: 10.1080/00958970701788859] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- A. SH. Al Alousi
- b The Public Authority of Applied Education, College of Health Studies , Kuwait
| | - M. R. Shehata
- a Faculty of Science, Department of Chemistry , Cairo University , Giza, Egypt
| | - M. M. Shoukry
- a Faculty of Science, Department of Chemistry , Cairo University , Giza, Egypt
| | - S. A. Hassan
- c Regional Center for Feed and Food, AGRIC Center , Egypt
| | - N. Mahmoud
- c Regional Center for Feed and Food, AGRIC Center , Egypt
| |
Collapse
|
37
|
Shehata MR, Shoukry MM, Nasr FMH, van Eldik R. Complex-formation reactions of dicholoro(S-methyl-l-cysteine)palladium(ii) with bio-relevant ligands. Labilization induced by S-donor chelates. Dalton Trans 2008:779-86. [DOI: 10.1039/b709332b] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
38
|
Computer augmented modelling studies of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid in 1,2-propanediol-water mixtures. JOURNAL OF THE SERBIAN CHEMICAL SOCIETY 2008. [DOI: 10.2298/jsc0812169v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Chemical speciation of Pb(II), Cd(II), Hg(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of L-glutamic acid was studied at 303 K in 0-60 vol. % 1,2-propanediol-water mixtures, whereby the ionic strength was maintained at 0.16 mol dm-3. The active forms of the ligand are + LH3, LH2 and LH-. The predominant detected species were ML, ML2, MLH, ML2H and ML2H2. The trend of the variation in the stability constants with changing dielectric constant of the medium is explained based on the cation stabilizing nature of the co-solvents, specific solvent-water interactions, charge dispersion and specific interactions of the co-solvent with the solute. The effect of systematic errors in the concentrations of the substances on the stability constants is in the order alkali > > acid > ligand > metal. The bioavailability and transportation of metals are explained based on distribution diagrams and stability constants.
Collapse
|
39
|
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.
Collapse
Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, Switzerland.
| | | | | | | | | | | |
Collapse
|
40
|
El-Sherif AA, Shoukry MM. Coordination properties of tridentate (N,O,O) heterocyclic alcohol (PDC) with Cu(II). Mixed ligand complex formation reactions of Cu(II) with PDC and some bio-relevant ligands. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2007; 66:691-700. [PMID: 16956788 DOI: 10.1016/j.saa.2006.04.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 04/10/2006] [Accepted: 04/14/2006] [Indexed: 05/11/2023]
Abstract
The formation equilibria of copper(II) complexes and the ternary complexes Cu(PDC)L (PDC=2,6-bis-(hydroxymethyl)-pyridine, HL=amino acid, amides or DNA constituents) have been investigated. Ternary complexes are formed by a simultaneous mechanism. The results showed the formation of Cu(PDC)L, Cu(PDC, H(-1))(L) and Cu(PDC, H(-2))(L) complexes. The concentration distribution of the complexes in solution is evaluated as a function of pH. The effect of dioxane as a solvent on the protonation constant of PDC and the formation constants of Cu(II) complexes are discussed. The thermodynamic parameters DeltaH degrees and DeltaS degrees calculated from the temperature dependence of the equilibrium constants are investigated.
Collapse
Affiliation(s)
- Ahmed A El-Sherif
- Department of Chemistry, Faculty of Science, Cairo University, Cairo, Egypt
| | | |
Collapse
|
41
|
Mohamed MM, Abd-Alla EM, El-Badawy AES. Dimethyltin(IV) complexes with zwitterionic buffers (Mes and Mops). J Organomet Chem 2007. [DOI: 10.1016/j.jorganchem.2006.12.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
42
|
Abstract
In this critical review we discuss recent advances in understanding the modes of interaction of metal ions with membrane proteins, including channels, pumps, transporters, ATP-binding cassette proteins, G-protein coupled receptors, kinases and respiratory enzymes. Such knowledge provides a basis for elucidating the mechanism of action of some classes of metallodrugs, and a stimulus for the further exploration of the coordination chemistry of metal ions in membranes. Such research offers promise for the discovery of new drugs with unusual modes of action. The article will be of interest to bioinorganic chemists, chemical biologists, biochemists, pharmacologists and medicinal chemists. (247 references).
Collapse
Affiliation(s)
- Xiangyang Liang
- School of Chemistry, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh, UKEH9 3JJ
| | | | | |
Collapse
|
43
|
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.
| | | |
Collapse
|
44
|
Neverov AA, Lu ZL, Maxwell CI, Mohamed MF, White CJ, Tsang JSW, Brown RS. Combination of a Dinuclear Zn2+ Complex and a Medium Effect Exerts a 1012-Fold Rate Enhancement of Cleavage of an RNA and DNA Model System. J Am Chem Soc 2006; 128:16398-405. [PMID: 17165797 DOI: 10.1021/ja0651714] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The catalytic ability of a dinuclear Zn2+ complex of 1,3-bis-N1-(1,5,9-triazacyclododecyl)propane (3) in promoting the cleavage of an RNA model, 2-hydroxypropyl-p-nitrophenyl phosphate (HPNPP, 1), and a DNA model, methyl p-nitrophenyl phosphate (MNPP, 4), was studied in methanol solution in the presence of added CH3O- at 25 degrees C. The di-Zn2+ complex (Zn2 :3), in the presence of 1 equiv of added methoxide, exhibits a second-order rate constant of (2.75 +/- 0.10) x 10(5) M(-1) s(-1) for the reaction with 1 at s(s)pH 9.5, this being 10(8)-fold larger than the k2 value for the CH3O- promoted reaction (kOCH3 = (2.56 +/- 0.16) x 10(-3) M(-1) s(-1)). The complex is also active toward the DNA model 4, exhibiting Michaelis-Menten kinetics with a KM and kmax of 0.37 +/- 0.07 mM and (4.1 +/- 0.3) x 10(-2) s(-1), respectively. Relative to the background reactions at s(s)pH 9.5, Zn2 :3 accelerates cleavage of each phosphate diester by a remarkable factor of 1012-fold. A kinetic scheme common to both substrates is discussed. The study shows that a simple model system comprising a dinuclear Zn2+ complex and a medium effect of the alcohol solvent achieves a catalytic reactivity that approaches enzymatic rates and is well beyond anything seen to date in water for the cleavage of these phosphate diesters.
Collapse
Affiliation(s)
- Alexei A Neverov
- Department of Chemistry, Queen's University, Kingston, Ontario, Canada, K7L 3N6
| | | | | | | | | | | | | |
Collapse
|
45
|
Mohamed MMA, Shehata MR, Shoukry MM. TRIMETHYLTIN(IV) COMPLEXES WITH SOME SELECTED DNA CONSTITUENTS. J COORD CHEM 2006. [DOI: 10.1080/00958970108022607] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Mahmoud M. A. Mohamed
- a Department of Sciences and Mathematics, Faculty of Education , Assuit University , New Valley, Egypt
| | - Mohamed R. Shehata
- b Department of Chemistry, Faculty of Science , Cairo University , Giza, Egypt
| | - Mohamed M. Shoukry
- b Department of Chemistry, Faculty of Science , Cairo University , Giza, Egypt
| |
Collapse
|
46
|
El-Sherif AA, Shoukry MM. Copper(II) complexes of imino-bis(methyl phosphonic acid) with some bio-relevant ligands. Equilibrium studies and hydrolysis of glycine methyl ester through complex formation. J COORD CHEM 2006. [DOI: 10.1080/00958970500055435] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ahmed A. El-Sherif
- a Department of Chemistry , Faculty of Science, Cairo University , Giza, Egypt
| | - Mohamed M. Shoukry
- a Department of Chemistry , Faculty of Science, Cairo University , Giza, Egypt
| |
Collapse
|
47
|
Mohamed MMA, Shoukry AA, Shoukry MM. Kinetics of base hydrolysis of α-amino acid esters catalyzed by the copper(II) complex of N,N,N′,N′-tetramethylethylenediamine (Me4en). INT J CHEM KINET 2006. [DOI: 10.1002/kin.20206] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
48
|
Altun Y. Study of Solvent Effects on the Protonation of Functional Group of Disubstituted Anilines: Factor Analysis Applied to the Correlation between Protonation Constants and Solvatochromic Parameters in Ethanol–Water Mixtures. MONATSHEFTE FUR CHEMIE 2005. [DOI: 10.1007/s00706-005-0371-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
49
|
On the Role of the Solvent and Substituent on the Protonation Equilibria of Di-Substituted Anilines in Dioxane–Water Mixed Solvents. J SOLUTION CHEM 2005. [DOI: 10.1007/s10953-005-8020-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
50
|
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.
Collapse
Affiliation(s)
- Helmut Sigel
- Department of Chemistry, Inorganic Chemistry, University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland.
| | | |
Collapse
|