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Lippert B, Sanz Miguel PJ. Assembly of nucleobases into rings and cages via metal ions. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2105144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Affiliation(s)
- Bernhard Lippert
- Fakultät Chemie und Chemische Biologie, TU Dortmund, Dortmund, Germany
| | - Pablo J. Sanz Miguel
- Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, Zaragoza, Spain
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Lippert B, Sanz Miguel PJ. Beyond sole models for the first steps of Pt-DNA interactions: Fundamental properties of mono(nucleobase) adducts of PtII coordination compounds. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Mixed guanine, adenine base quartets: possible roles of protons and metal ions in their stabilization. J Biol Inorg Chem 2017; 23:41-49. [PMID: 29218641 PMCID: PMC5756560 DOI: 10.1007/s00775-017-1507-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 10/18/2017] [Indexed: 11/17/2022]
Abstract
Structural variations of the well-known guanine quartet (G4) motif in nucleic acid structures, namely substitution of two guanine bases (G) by two adenine (A) nucleobases in mutual trans positions, are discussed and studied by density functional theory (DFT) methods. This work was initiated by three findings, namely (1) that GA mismatches are compatible with complementary pairing patterns in duplex-DNA structures and can, in principle, be extended to quartet structures, (2) that GA pairs can come in several variations, including with a N1 protonated adeninium moiety (AH), and (3) that cross-linking of the major donor sites of purine nucleobases (N1 and N7) by transition metal ions of linear coordination geometries produces planar purine quartets, as demonstrated by some of us in the past. Here, possible structures of mixed AGAG quartets both in the presence of protons and alkali metal ions are discussed, and in particular, the existence of a putative four-purine, two-metal motif.
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The exocyclic amino group of adenine in Pt II and Pd II complexes: a critical comparison of the X-ray crystallographic structural data and gas phase calculations. J Biol Inorg Chem 2017; 22:567-579. [PMID: 28315011 DOI: 10.1007/s00775-017-1448-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 02/28/2017] [Indexed: 12/30/2022]
Abstract
A detailed computational (DFT level of theory) study regarding the nature of the exocyclic amino group, N6H2, of the model nucleobase 9-methyladenine (9MeA) and its protonated (9MeAH+) and deprotonated forms (9MeA-H), free and metal-complexed, has been conducted. The metals are PtII and PdII, bonded to nitrogen-containing co-ligands (NH3, dien, bpy), with N1, N6, and N7 being the metal-binding sites, individually or in different combinations. The results obtained from gas phase calculations are critically compared with X-ray crystallography data, whenever possible. In the majority of cases, there is good qualitative agreement between calculated and experimentally determined C6-N6 bond lengths, but calculated values always show a trend to larger values, by 0.02-0.08 Å. Both methods indicate, with few exceptions, a high degree of double-bond character of C6-N6, consistent with an essentially sp2-hybridized N6 atom. The shortest values for C6-N6 distances in X-ray crystal structures are around 1.30 Å. Exceptions refer to cases in which DFT calculations suggest the existence of a hydrogen bond with N6H2 acting as a H bond acceptor, hence a situation with N6 having undergone a substantial hybridization shift toward sp3. Nevertheless, even in these cases the C6-N6 bond (1.392 Å) is still halfway between a typical C-N single bond (1.48 Å) and a typical C=N double bond (1.28 Å). This scenario is, however, not borne out by X-ray crystallographic results, and is attributed to the absence of counter anions and solvent molecules in the calculated structures.
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Štarha P, Vančo J, Trávníček Z. Platinum complexes containing adenine-based ligands: An overview of selected structural features. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2016.09.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Ibáñez S, Mihály B, Sanz Miguel PJ, Steinborn D, Pretzer I, Hiller W, Lippert B. The challenge of deciphering linkage isomers in mixtures of oligomeric complexes derived from 9-methyladenine and trans-(NH3)2Pt(II) units. Chemistry 2015; 21:5794-806. [PMID: 25737270 DOI: 10.1002/chem.201406378] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Indexed: 11/11/2022]
Abstract
Metal coordination to N9-substituted adenines, such as the model nucleobase 9-methyladenine (9MeA), under neutral or weakly acidic pH conditions in water preferably occurs at N1 and/or N7. This leads, not only to mononuclear linkage isomers with N1 or N7 binding, but also to species that involve both N1 and N7 metal binding in the form of dinuclear or oligomeric species. Application of a trans-(NH3)2Pt(II) unit and restriction of metal coordination to the N1 and N7 sites and the size of the oligomer to four metal entities generates over 50 possible isomers, which display different feasible connectivities. Slowly interconverting rotamers are not included in this number. Based on (1)H NMR spectroscopic analysis, a qualitative assessment of the spectroscopic features of N1,N7-bridged species was attempted. By studying the solution behavior of selected isolated and structurally characterized compounds, such as trans-[PtCl(9MeA-N7)(NH3)2]ClO4⋅2H2O or trans,trans-[{PtCl(NH3)2}2(9MeA-N1,N7)][ClO4]2⋅H2O, and also by application of a 9MeA complex with an (NH3)3Pt(II) entity at N7, [Pt(9MeA-N7)(NH3)3][NO3]2, which blocks further cross-link formation at the N7 site, basic NMR spectroscopic signatures of N1,N7-bridged Pt(II) complexes were identified. Among others, the trinuclear complex trans-[Pt(NH3)2{μ-(N1-9MeA-N7)Pt(NH3)3}2][ClO4]6⋅2H2O was crystallized and its rotational isomerism in aqueous solution was studied by NMR spectroscopy and DFT calculations. Interestingly, simultaneous Pt(II) coordination to N1 and N7 acidifies the exocyclic amino group of the two 9MeA ligands sufficiently to permit replacement of one proton each by a bridging heterometal ion, Hg(II) or Cu(II), under mild conditions in water.
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Affiliation(s)
- Susana Ibáñez
- Fakultät Chemie und Chemische Biologie (CCB), Technische Universität Dortmund, Otto-Hahn-Straße 6, 44221 Dortmund (Germany), Fax: (+49) 231-755-3797
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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: 0.7] [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.
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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.
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Vellé A, Cebollada A, Iglesias M, Sanz Miguel PJ. Argentophilicity as Essential Driving Force for a Dynamic Cation–Cation Host–Guest System: [Ag(acetonitrile)2]+⊂[Ag2(bis-NHC)2]2+ (NHC = N-Heterocyclic Carbene). Inorg Chem 2014; 53:10654-9. [DOI: 10.1021/ic501715h] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Alba Vellé
- Departamento de Química Inorgánica, Instituto de Síntesis
Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Andrea Cebollada
- Departamento de Química Inorgánica, Instituto de Síntesis
Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Manuel Iglesias
- Departamento de Química Inorgánica, Instituto de Síntesis
Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
| | - Pablo J. Sanz Miguel
- Departamento de Química Inorgánica, Instituto de Síntesis
Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
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