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Laiolo J, Graikioti DG, Barbieri CL, Joray MB, Antoniou AI, Vera DMA, Athanassopoulos CM, Carpinella MC. Novel betulin derivatives as multidrug reversal agents targeting P-glycoprotein. Sci Rep 2024; 14:70. [PMID: 38167542 PMCID: PMC10762177 DOI: 10.1038/s41598-023-49939-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024] Open
Abstract
Chemotherapy is a powerful means of cancer treatment but its efficacy is compromised by the emergence of multidrug resistance (MDR), mainly linked to the efflux transporter ABCB1/P-glycoprotein (P-gp). Based on the chemical structure of betulin, identified in our previous work as an effective modulator of the P-gp function, a series of analogs were designed, synthesized and evaluated as a source of novel inhibitors. Compounds 6g and 6i inhibited rhodamine 123 efflux in the P-gp overexpressed leukemia cells, K562/Dox, at concentrations of 0.19 µM and 0.39 µM, respectively, and increased the intracellular accumulation of doxorubicin at the submicromolar concentration of 0.098 µM. Compounds 6g and 6i were able to restore the sensitivity of K562/Dox to Dox at 0.024 µM and 0.19 µM, respectively. Structure-activity relationship analysis and molecular modeling revealed important information about the structural features conferring activity. All the active compounds fitted in a specific region involving mainly transmembrane helices (TMH) 4-6 from one homologous half and TMH 7 and 12 from the other, also showing close contacts with TMH 6 and 12. Compounds that bound preferentially to another region were inactive, regardless of their free energy of binding. It should be noted that compounds 6g and 6i were devoid of toxic effects against peripheral blood mononuclear normal cells and erythrocytes. The data obtained indicates that both compounds might be proposed as scaffolds for obtaining promising P-gp inhibitors for overcoming MDR.
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Affiliation(s)
- Jerónimo Laiolo
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC, Universidad Católica de Córdoba, Córdoba, Argentina
| | - Dafni G Graikioti
- Synthetic Organic Chemistry Laboratory, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Cecilia L Barbieri
- Department of Chemistry and Biochemistry, College of Exact and Natural Sciences, Universidad Nacional de Mar del Plata - QUIAMM - INBIOTEC CONICET, Mar del Plata, Argentina
| | - Mariana B Joray
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC and CIDIE CONICET-UCC, Universidad Católica de Córdoba, Córdoba, Argentina
| | - Antonia I Antoniou
- Synthetic Organic Chemistry Laboratory, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - D Mariano A Vera
- Department of Chemistry and Biochemistry, College of Exact and Natural Sciences, Universidad Nacional de Mar del Plata - QUIAMM - INBIOTEC CONICET, Mar del Plata, Argentina.
| | | | - María C Carpinella
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC and CIDIE CONICET-UCC, Universidad Católica de Córdoba, Córdoba, Argentina.
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Lanza PA, Dusso D, Mena LD, Parise AR, Moyano EL, Chesta CA, Vera DMA. Why and how could an aliphatic bridge allow for a long-range photoinduced charge separation in Tröger’s bases derivatives. J Photochem Photobiol A Chem 2023. [DOI: 10.1016/j.jphotochem.2023.114699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
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Llorens de los Ríos MC, Lanza PA, Barbieri CL, González ML, Chabán MF, Soria G, Vera DMA, Carpinella MC, Joray MB. The thiophene α-terthienylmethanol isolated from Tagetes minuta inhibits angiogenesis by targeting protein kinase C isozymes α and β2. Front Pharmacol 2022; 13:1007790. [PMID: 36313304 PMCID: PMC9597362 DOI: 10.3389/fphar.2022.1007790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 09/30/2022] [Indexed: 11/24/2022] Open
Abstract
Background: Tumor angiogenesis is considered as a crucial pathologic feature of cancer with a key role in multidrug resistance (MDR). Adverse effects of the currently available drugs and the development of resistance to these remain as the hardest obstacles to defeat. Objetive: This work explores flora from Argentina as a source of new chemical entities with antiangiogenic activity. Methods: Tube formation assay using bovine aortic endothelial cells (BAECs) was the experiment of choice to assess antiangiogenic activity. The effect of the pure compound in cell invasiveness was investigated through the trans-well migration assay. The inhibitory effect of the pure compound on VEGFR-2 and PKC isozymes α and β2 activation was studied by molecular and massive dynamic simulations. Cytotoxicity on peripheral blood mononuclear cells and erythrocyte cells was evaluated by means of MTT and hemolysis assay, respectively. In silico prediction of pharmacological properties (ADME) and evaluation of drug-likeness features were performed using the SwissADME online tool. Results: Among the plants screened, T. minuta, showed an outstanding effect with an IC50 of 33.6 ± 3.4 μg/ml. Bio-guided isolation yielded the terthiophene α-terthienylmethanol as its active metabolite. This compound inhibited VEGF-induced tube formation with an IC50 of 2.7 ± 0.4 μM and significantly impaired the invasiveness of bovine aortic endothelial cells (BAECs) as well as of the highly aggressive breast cancer cells, MDA-MB-231, when tested at 10 μM. Direct VEGFR-2 and PKC inhibition were both explored by means of massive molecular dynamics simulations. The results obtained validated the inhibitory effect on protein kinase C (PKC) isozymes α and β2 as the main mechanism underlying its antiangiogenic activity. α-terthienylmethanol showed no evidence of toxicity against peripheral blood mononuclear and erythrocyte cells. Conclusion: These findings support this thiophene as a promising antiangiogenic phytochemical to fight against several types of cancer mainly those with MDR phenotype.
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Affiliation(s)
| | - Priscila A. Lanza
- Department of Chemistry and Biochemistry, QUIAMM–INBIOTEC–CONICET, College of Exact and Natural Sciences, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Cecilia L. Barbieri
- Department of Chemistry and Biochemistry, QUIAMM–INBIOTEC–CONICET, College of Exact and Natural Sciences, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - María L. González
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC, School of Chemistry, Universidad Católica de Córdoba, Córdoba, Argentina
| | - Macarena Funes Chabán
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC, School of Chemistry, Universidad Católica de Córdoba, Córdoba, Argentina
| | - Gastón Soria
- CIBICI CONICET and Department of Clinical Biochemistry, Faculty of Chemical Science, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - D. Mariano A. Vera
- Department of Chemistry and Biochemistry, QUIAMM–INBIOTEC–CONICET, College of Exact and Natural Sciences, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
- *Correspondence: D. Mariano A. Vera, ; María C. Carpinella, ; Mariana B. Joray,
| | - María C. Carpinella
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC, School of Chemistry, Universidad Católica de Córdoba, Córdoba, Argentina
- *Correspondence: D. Mariano A. Vera, ; María C. Carpinella, ; Mariana B. Joray,
| | - Mariana B. Joray
- Fine Chemical and Natural Products Laboratory, IRNASUS CONICET-UCC, School of Chemistry, Universidad Católica de Córdoba, Córdoba, Argentina
- *Correspondence: D. Mariano A. Vera, ; María C. Carpinella, ; Mariana B. Joray,
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Laiolo J, Barbieri CL, Joray MB, Lanza PA, Palacios SM, Vera DMA, Carpinella MC. Plant extracts and betulin from Ligaria cuneifolia inhibit P-glycoprotein function in leukemia cells. Food Chem Toxicol 2021; 147:111922. [DOI: 10.1016/j.fct.2020.111922] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/30/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022]
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Mena LD, Vera DMA, Baumgartner MT. Impact of benzannulation on ESIPT in 2-(2'-hydroxyphenyl)-oxazoles: a unified perspective in terms of excited-state aromaticity and intramolecular charge transfer. RSC Adv 2020; 10:39049-39059. [PMID: 35518439 PMCID: PMC9057364 DOI: 10.1039/d0ra05802e] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/14/2020] [Indexed: 01/06/2023] Open
Abstract
Hydroxyphenyl-azoles are among the most popular ESIPT (Excited State Intramolecular Proton Transfer) scaffolds and as such, they have been thoroughly studied. Nevertheless, some aspects regarding the interplay between the emissive properties of these fluorophores and the size of their π-conjugated framework remain controversial. Previous studies have demonstrated that benzannulation of 2′-hydroxyphenyl-oxazole at the phenol group of the molecule can lead to either red- or blue-shifted fluorescence emission, depending on the site where it occurs. In this report, benzannulation at the heterocyclic unit (the oxazole site) is analysed in order to get the whole picture. The extension of π-conjugation does not significantly affect the ESIPT emission wavelength, but it leads instead to higher energy barriers for proton transfer in the first excited singlet state, as a consequence of dramatic changes in the charge transfer character of excitation caused by successive benzannulation. Theoretical calculations revealed an interesting connection between intramolecular charge transfer and excited-state aromaticity in the S1 state. The theoretical approach presented herein allows the behaviour of hydroxyphenyl-oxazoles in the excited state to be rationalized and, more generally, a deeper understanding of the factors governing the ESIPT process to be obtained, a crucial point in the design of new and efficient fluorophores. Benzannulation of a typical fluorophore reveals the interplay between ESIPT, excited-state aromaticity and intramolecular charge transfer.![]()
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Affiliation(s)
- Leandro D Mena
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria Córdoba X5000HUA Argentina
| | - D M A Vera
- QUIAMM-INBIOTEC-Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata Mar del Plata Argentina
| | - María T Baumgartner
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria Córdoba X5000HUA Argentina
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Lanza PA, Dusso D, Ramirez CL, Parise AR, Chesta CA, Moyano EL, Vera DMA. Uncovering the Mechanism Leading to the Synthesis of Symmetric and Asymmetric Tröger′s Bases. European J Org Chem 2019. [DOI: 10.1002/ejoc.201901141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Priscila A. Lanza
- QUIAMM-INBIOTEC. Department of Chemistry; Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Mar del Plata; Mar del Plata Argentina
| | - Diego Dusso
- INFIQC; Department of Organic Chemistry; Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - Cristina L. Ramirez
- Department of Chemistry; Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Mar del Plata; Mar del Plata Argentina
| | - Alejandro R. Parise
- QUIAMM-INBIOTEC. Department of Chemistry; Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Mar del Plata; Mar del Plata Argentina
| | - Carlos A. Chesta
- IITEMA; Department of Chemistry; Facultad de Ciencias Físicoquimicas y Naturales; Universidad Nacional de Rio Cuarto; Las Higueras Argentina
| | - E. Laura Moyano
- INFIQC; Department of Organic Chemistry; Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - D. Mariano A. Vera
- QUIAMM-INBIOTEC. Department of Chemistry; Facultad de Ciencias Exactas y Naturales; Universidad Nacional de Mar del Plata; Mar del Plata Argentina
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Mena LD, Vera DMA, Baumgartner MT, Jimenez LB. Adiabatic deprotonation as an important competing pathway to ESIPT in photoacidic 2-phenylphenols. Phys Chem Chem Phys 2019; 21:12231-12240. [PMID: 31134981 DOI: 10.1039/c9cp02028d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
ESIPT (Excited State Intramolecular Proton Transfer) to C atom in 2-phenylphenol is known to be an intrinsically inefficient process. However, to the best of our knowledge, a structure-ESIPT efficiency relationship has not been elucidated yet. Here, we show that there exists a competitive interplay between photoacidity and ESIPT efficiency for the 2-phenylphenol system. The attachment of electron withdrawing groups to the phenol moiety promotes adiabatic deprotonation in the excited state and diminishes the charge transfer character of the excitations, and both these factors contribute in decreasing the ESIPT reaction yield. On the other hand, unfavorable conformational distribution in the ground state also appears as another important aspect responsible for the low ESIPT extent of 2-phenylphenol. A new derivative bearing electron donating, bulky substituents at ortho and para positions of the phenol ring shows an outstanding ESIPT performance, which demonstrates that the efficiency of the process can be significantly enhanced by modifying the substitution pattern. We anticipate that our results will help to guide the molecular designing of new compounds with high ESIPT efficiency.
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Affiliation(s)
- Leandro D Mena
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
| | - D M A Vera
- QUIAMM-INBIOTEC-Departamento de Química, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Mar del Plata, Argentina
| | - Maria T Baumgartner
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
| | - Liliana B Jimenez
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba Ciudad Universitaria, Córdoba, Argentina.
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Laiolo J, Tomašič T, Vera DMA, González ML, Lanza PA, Gancedo SN, Hodnik Ž, Peterlin Mašič L, Kikelj D, Carpinella MC. Analogues of the Lignan Pinoresinol as Novel Lead Compounds for P-glycoprotein (P-gp) Inhibitors. ACS Med Chem Lett 2018; 9:1186-1192. [PMID: 30613324 DOI: 10.1021/acsmedchemlett.8b00324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 11/21/2018] [Indexed: 12/24/2022] Open
Abstract
To find novel P-gp-inhibitors, a library of pregnane X receptor (PXR) ligands and the ZINC DrugsNow library were superimposed on the P-gp inhibitor (+)-pinoresinol (1) used as a query for a three-dimensional similarity search. After determining the TanimotoCombo index of similarity with 1, eight compounds from the PXR library and two ZINC compounds were selected for biological evaluation. The P-gp inhibition study showed that compounds 7, 8, and 9 successfully increased intracellular doxorubicin (DOX) accumulation in the P-gp overexpressed Lucena 1 cells from 25, 12.5, and 6.25 μM, respectively. Among a series of analogues of 9, compounds 26-30 were shown to be active, with 26 and 27 causing a significant increase in DOX accumulation from 1.56 μM and rendering Lucena 1 sensitive to DOX from 1.56 and 0.78 μM, respectively. Molecular modeling studies showed that both compounds bind to the P-gp at transmembrane helices (TMH) 4, 5, and 6, with 27 also showing contacts with TMH 3.
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Affiliation(s)
- Jerónimo Laiolo
- Research Institute of Natural Resources and Sustainability José Sánchez Labrador S.J. (IRNASUS-CONICET), School of Chemistry, Catholic University of Córdoba, Córdoba, Argentina
| | - Tihomir Tomašič
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Republic of Slovenia
| | - D. Mariano A. Vera
- Department of Chemistry, QUIAMM−INBIOTEC−CONICET, College of Exact and Natural Sciences, National University of Mar del Plata, Mar del Plata, Argentina
| | - María L. González
- Research Institute of Natural Resources and Sustainability José Sánchez Labrador S.J. (IRNASUS-CONICET), School of Chemistry, Catholic University of Córdoba, Córdoba, Argentina
| | - Priscila A. Lanza
- Department of Chemistry, QUIAMM−INBIOTEC−CONICET, College of Exact and Natural Sciences, National University of Mar del Plata, Mar del Plata, Argentina
| | - Samanta N. Gancedo
- Department of Chemistry, QUIAMM−INBIOTEC−CONICET, College of Exact and Natural Sciences, National University of Mar del Plata, Mar del Plata, Argentina
| | - Žiga Hodnik
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Republic of Slovenia
| | | | - Danijel Kikelj
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Republic of Slovenia
| | - María C. Carpinella
- Research Institute of Natural Resources and Sustainability José Sánchez Labrador S.J. (IRNASUS-CONICET), School of Chemistry, Catholic University of Córdoba, Córdoba, Argentina
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Stocchi N, Revuelta MV, Castronuovo PAL, Vera DMA, Ten Have A. Molecular dynamics and structure function analysis show that substrate binding and specificity are major forces in the functional diversification of Eqolisins. BMC Bioinformatics 2018; 19:338. [PMID: 30249179 PMCID: PMC6154417 DOI: 10.1186/s12859-018-2348-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 08/29/2018] [Indexed: 11/30/2022] Open
Abstract
Background Eqolisins are rare acid proteases found in archaea, bacteria and fungi. Certain fungi secrete acids as part of their lifestyle and interestingly these also have many eqolisin paralogs, up to nine paralogs have been recorded. This suggests a process of functional redundancy and diversification has occurred, which was the subject of the research we performed and describe here. Results We identified eqolisin homologs by means of iterative HMMER analysis of the NR database. The identified sequences were scrutinized for which new hallmarks were identified by molecular dynamics simulations of mutants in highly conserved positions, using the structure of an eqolisin that was crystallized in the presence of a transition state inhibitor. Four conserved glycines were shown to be important for functionality. A substitution of W67F is shown to be accompanied by the L105W substitution. Molecular dynamics shows that the W67 binds to the substrate via a π-π stacking and a salt bridge, the latter being stronger in a virtual W67F/L105W double mutant of the resolved structure of Scytalido-carboxyl peptidase-B (PDB ID: 2IFW). Additional problematic mutations are discussed. Upon sequence scrutiny we obtained a set of 233 sequences that was used to reconstruct a Bayesian phylogenetic tree. We identified 14 putative specificity determining positions (SDPs) of which four are explained by mere structural explanations and nine seem to correspond to functional diversification related with substrate binding and specificity. A first sub-network of SDPs is related to substrate specificity whereas the second sub-network seems to affect the dynamics of three loops that are involved in substrate binding. Conclusion The eqolisins form a small superfamily of acid proteases with nevertheless many paralogs in acidic fungi. Functional redundancy has resulted in diversification related to substrate specificity and substrate binding. Electronic supplementary material The online version of this article (10.1186/s12859-018-2348-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nicolás Stocchi
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina
| | - María Victoria Revuelta
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.,Pressent address: Department of Medicine, Hematology and Oncology Division, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Priscila Ailín Lanza Castronuovo
- QUIAMM-INBIOTEC-CONICET, Department of Chemistry - Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, 7600, Mar del Plata, Argentina
| | - D Mariano A Vera
- QUIAMM-INBIOTEC-CONICET, Department of Chemistry - Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, 7600, Mar del Plata, Argentina
| | - Arjen Ten Have
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
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Komrovsky F, Sperandeo NR, Vera DMA, Caira MR, Mazzieri MR. X-ray, DFT, FTIR and thermal study of the antimicrobial N-benzenesulfonyl-1H-1,2,3-benzotriazole. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Colomer JP, Sciú ML, Ramirez CL, Soria-Castro SM, Vera DMA, Moyano EL. Front Cover: Thermal Ring-Opening of Pyrazolo[3,4- d
][1,2,3]triazin-4-ones: An Experimental and Theoretical Study (Eur. J. Org. Chem. 13/2018). European J Org Chem 2018. [DOI: 10.1002/ejoc.201800445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Juan P. Colomer
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - María L. Sciú
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - Cristina L. Ramirez
- QUIAMM-INBIOTEC; Dept. of Chemistry; School of Exact and Natural Sciences; National University of Mar del Plata; Mar del Plata Argentina
| | - Silvia M. Soria-Castro
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - D. Mariano A. Vera
- QUIAMM-INBIOTEC; Dept. of Chemistry; School of Exact and Natural Sciences; National University of Mar del Plata; Mar del Plata Argentina
| | - Elizabeth L. Moyano
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
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Colomer JP, Sciú ML, Ramirez CL, Soria-Castro SM, Vera DMA, Moyano EL. Thermal Ring-Opening of Pyrazolo[3,4-d
][1,2,3]triazin-4-ones: An Experimental and Theoretical Study. European J Org Chem 2018. [DOI: 10.1002/ejoc.201701538] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Juan P. Colomer
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - María L. Sciú
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - Cristina L. Ramirez
- QUIAMM-INBIOTEC; Dept. of Chemistry; School of Exact and Natural Sciences; National University of Mar del Plata; Mar del Plata Argentina
| | - Silvia M. Soria-Castro
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
| | - D. Mariano A. Vera
- QUIAMM-INBIOTEC; Dept. of Chemistry; School of Exact and Natural Sciences; National University of Mar del Plata; Mar del Plata Argentina
| | - Elizabeth L. Moyano
- INFIQC; Department of Organic Chemistry; National University of Córdoba; Córdoba Argentina
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Malvacio I, Cuzzolin A, Sturlese M, Vera DMA, Moyano EL, Moro S. Synthesis and preliminary structure-activity relationship study of 2-aryl-2H-pyrazolo[4,3-c]quinolin-3-ones as potential checkpoint kinase 1 (Chk1) inhibitors. J Enzyme Inhib Med Chem 2017; 33:171-183. [PMID: 29210298 PMCID: PMC6010083 DOI: 10.1080/14756366.2017.1404592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The serine-threonine checkpoint kinase 1 (Chk1) plays a critical role in the cell cycle arrest in response to DNA damage. In the last decade, Chk1 inhibitors have emerged as a novel therapeutic strategy to potentiate the anti-tumour efficacy of cytotoxic chemotherapeutic agents. In the search for new Chk1 inhibitors, a congeneric series of 2-aryl-2 H-pyrazolo[4,3-c]quinolin-3-one (PQ) was evaluated by in-vitro and in-silico approaches for the first time. A total of 30 PQ structures were synthesised in good to excellent yields using conventional or microwave heating, highlighting that 14 of them are new chemical entities. Noteworthy, in this preliminary study two compounds 4e2 and 4h2 have shown a modest but significant reduction in the basal activity of the Chk1 kinase. Starting from these preliminary results, we have designed the second generation of analogous in this class and further studies are in progress in our laboratories.
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Affiliation(s)
- Ivana Malvacio
- a Department of Organic Chemistry, INFIQC, School of Chemical Sciences , National University of Cordoba , Cordoba , Argentina.,b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - Alberto Cuzzolin
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - Mattia Sturlese
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
| | - D Mariano A Vera
- c Department of Chemistry, QUIAMM-INBIOTEC, School of Exact and Natural Sciences , National University of Mar del Plata , Mar del Plata , Buenos Aires , Argentina
| | - E Laura Moyano
- a Department of Organic Chemistry, INFIQC, School of Chemical Sciences , National University of Cordoba , Cordoba , Argentina
| | - Stefano Moro
- b Molecular Modeling Section (MMS), Dipartimento di Scienze Farmaceutiche , Università degli Studi di Padova , via Marzolo, Padova , Italy
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González ML, Vera DMA, Laiolo J, Joray MB, Maccioni M, Palacios SM, Molina G, Lanza PA, Gancedo S, Rumjanek V, Carpinella MC. Mechanism Underlying the Reversal of Drug Resistance in P-Glycoprotein-Expressing Leukemia Cells by Pinoresinol and the Study of a Derivative. Front Pharmacol 2017; 8:205. [PMID: 28487651 PMCID: PMC5403950 DOI: 10.3389/fphar.2017.00205] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/31/2017] [Indexed: 11/17/2022] Open
Abstract
P-glycoprotein (P-gp) is a membrane protein associated with multidrug resistance (MDR) due to its key role in mediating the traffic of chemotherapeutic drugs outside cancer cells, leading to a cellular response that hinders efforts toward successful therapy. With the aim of finding agents that circumvent the MDR phenotype mediated by P-gp, 15 compounds isolated from native and naturalized plants of Argentina were screened. Among these, the non-cytotoxic lignan (±) pinoresinol successfully restored sensitivity to doxorubicin from 7 μM in the P-gp overexpressed human myelogenous leukemia cells, Lucena 1. This resistance-reversing effect was confirmed by competitively increasing the intracellular doxorubicin accumulation and by significantly inhibiting the efflux of doxorubicin and, to a lesser extent, that of rhodamine 123. The activity obtained was similar to that observed with verapamil. No such results were observed in the sensitive parental K562 cell line. To gain deeper insight into the mode of action of pinoresinol, its effect on P-gp function and expression was examined. The docking simulations indicated that the lignan bound to P-gp at the apex of the V-shaped transmembrane cavity, involving transmembrane helices 4, 5, and 6, and partially overlapped the binding region of tariquidar, which was used as a positive control. These results would shed some light on the nature of its interaction with P-gp at molecular level and merit further mechanistic and kinetic studies. In addition, it showed a maximum 29% activation of ATP hydrolysis and antagonized verapamil-stimulated ATPase activity with an IC50 of 20.9 μM. On the other hand, pinoresinol decreased the presence of P-gp in the cell surface. Derivatives of pinoresinol with improved activity were identified by docking studies. The most promising one, the non-cytotoxic 1-acetoxypinoresinol, caused a reversion of doxorubicin resistance from 0.11 μM and thus higher activity than the lead compound. It also caused a significant increase in doxorubicin accumulation. Results were similar to those observed with verapamil. The results obtained positioned these compounds as potential candidates for effective agents to overcome P-gp-mediated MDR, leading to better outcomes for leukemia chemotherapy.
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Affiliation(s)
- María L González
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
| | - D Mariano A Vera
- Department of Chemistry, QUIAMM-INBIOTEC-CONICET, College of Exact and Natural Sciences, National University of Mar del PlataMar del Plata, Argentina
| | - Jerónimo Laiolo
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
| | - Mariana B Joray
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
| | - Mariana Maccioni
- Immunology, Department of Biochemical Chemistry, CIBICI-CONICET, School of Chemical Sciences, National University of CórdobaCórdoba, Argentina
| | - Sara M Palacios
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
| | - Gabriela Molina
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
| | - Priscila A Lanza
- Department of Chemistry, QUIAMM-INBIOTEC-CONICET, College of Exact and Natural Sciences, National University of Mar del PlataMar del Plata, Argentina
| | - Samanta Gancedo
- Immunology, Department of Biochemical Chemistry, CIBICI-CONICET, School of Chemical Sciences, National University of CórdobaCórdoba, Argentina
| | - Vivian Rumjanek
- Institute of Medical Biochemistry, Federal University of Rio de JaneiroRio de Janeiro, Brazil
| | - María C Carpinella
- Fine Chemical and Natural Products Laboratory, School of Chemistry, Catholic University of CórdobaCórdoba, Argentina
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15
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Borioni JL, Puiatti M, Vera DMA, Pierini AB. In search of the best DFT functional for dealing with organic anionic species. Phys Chem Chem Phys 2017; 19:9189-9198. [DOI: 10.1039/c6cp06163j] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
“And the winner is…” This work assesses the ability of different Density Functional Theory (DFT) functionals for a proper treatment of organic anionic species.
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Affiliation(s)
- José L. Borioni
- INFIQC – CONICET
- Instituto de Investigaciones en Físicoquímica de Córdoba
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
| | - Marcelo Puiatti
- INFIQC – CONICET
- Instituto de Investigaciones en Físicoquímica de Córdoba
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
| | - D. Mariano A. Vera
- QUIAMM-IMBIOTEC-Departamento de Química
- Facultad de Ciencias Exactas y Naturales
- Universidad Nacional de Mar del Plata
- Mar del Plata
- Argentina
| | - Adriana B. Pierini
- INFIQC – CONICET
- Instituto de Investigaciones en Físicoquímica de Córdoba
- Departamento de Química Orgánica
- Facultad de Ciencias Químicas
- Universidad Nacional de Córdoba
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16
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Malvacio I, Moyano EL, Vera DMA. Gas-phase synthesis of 3-carboethoxy-quinolin-4-ones. A comprehensive computational mechanistic study to uncover the dark side of the Gould–Jacobs reaction. RSC Adv 2016. [DOI: 10.1039/c6ra11986g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
A set of 3-carboethoxy-quinolin-4-ones were synthesized from diethyl 2-((arylamino)methylene) malonates through a Gould–Jacobs cyclization using flash vacuum pyrolysis (FVP). A detailed mechanistic study was done using DFT and Coupled Clusters models.
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Affiliation(s)
- Ivana Malvacio
- QUIAMM-INBIOTEC – Department of Chemistry
- School of Exact and Natural Sciences
- National University of Mar del Plata
- Mar del Plata
- Argentina
| | - E. Laura Moyano
- INFIQC – Department of Organic Chemistry
- School of Chemical Sciences
- National University of Córdoba
- Córdoba
- Argentina
| | - D. Mariano A. Vera
- QUIAMM-INBIOTEC – Department of Chemistry
- School of Exact and Natural Sciences
- National University of Mar del Plata
- Mar del Plata
- Argentina
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17
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Jara GE, Vera DMA, Pierini AB. Binding of modulators to mouse and human multidrug resistance P-glycoprotein. A computational study. J Mol Graph Model 2013; 46:10-21. [DOI: 10.1016/j.jmgm.2013.09.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 08/08/2013] [Accepted: 09/02/2013] [Indexed: 02/02/2023]
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Kourtesi C, Ball AR, Huang YY, Jachak SM, Vera DMA, Khondkar P, Gibbons S, Hamblin MR, Tegos GP. Microbial efflux systems and inhibitors: approaches to drug discovery and the challenge of clinical implementation. Open Microbiol J 2013; 7:34-52. [PMID: 23569468 PMCID: PMC3617545 DOI: 10.2174/1874285801307010034] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 01/22/2013] [Accepted: 01/23/2013] [Indexed: 12/16/2022] Open
Abstract
Conventional antimicrobials are increasingly ineffective due to the emergence of multidrug-resistance among pathogenic microorganisms. The need to overcome these deficiencies has triggered exploration for novel and unconventional approaches to controlling microbial infections. Multidrug efflux systems (MES) have been a profound obstacle in the successful deployment of antimicrobials. The discovery of small molecule efflux system blockers has been an active and rapidly expanding research discipline. A major theme in this platform involves efflux pump inhibitors (EPIs) from natural sources. The discovery methodologies and the available number of natural EPI-chemotypes are increasing. Advances in our understanding of microbial physiology have shed light on a series of pathways and phenotypes where the role of efflux systems is pivotal. Complementing existing antimicrobial discovery platforms such as photodynamic therapy (PDT) with efflux inhibition is a subject under investigation. This core information is a stepping stone in the challenge of highlighting an effective drug development path for EPIs since the puzzle of clinical implementation remains unsolved. This review summarizes advances in the path of EPI discovery, discusses potential avenues of EPI implementation and development, and underlines the need for highly informative and comprehensive translational approaches.
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Affiliation(s)
- Christina Kourtesi
- Department of Pathology, University of New Mexico, School of Medicine, Albuquerque, NM, USA ; Department of Pathology, Faculty of Medicine, National & Kapodistrian University of Athens, Greece
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19
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Negre CFA, Jara GE, Vera DMA, Pierini AB, Sánchez CG. Detailed analysis of water structure in a solvent mediated electron tunneling mechanism. J Phys Condens Matter 2011; 23:245305. [PMID: 21628786 DOI: 10.1088/0953-8984/23/24/245305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This work aims at describing the water structure characteristics that influence the electron transfer superexchange mechanism by explicitly calculating the solvent mediated conductance between the donor and acceptor in a generic pair. The method employed here is based on the non-equilibrium Green function formalism for calculating the conductance over solvent trajectories previously determined by molecular dynamics methods. A non-exponential dependence of the conductance is observed with respect to the distance between the donor and the acceptor. Local fluctuations of the solvent structure are responsible for the non-monotonic dependence, mainly due to the formation of solvent bridges that act as a molecular wire connecting the sites. This shortcutting phenomenon is observed for certain ranges of distances between the donor and acceptor in the pair. Charge on the sites strongly affects the local solvent structure and causes qualitative changes in the distance dependence of the tunneling probability.
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Affiliation(s)
- Christian F A Negre
- Departamento de Matemática y Física, Facultad de Ciencias Químicas, INFIQC, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
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20
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Ramírez CL, Pegoraro C, Trupp L, Bruttomesso A, Amorebieta V, Vera DMA, Parise AR. Charge transfer properties of Tröger base derivatives. Phys Chem Chem Phys 2011; 13:20076-80. [DOI: 10.1039/c1cp22086a] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Puiatti M, Vera DMA, Pierini AB. In search for an optimal methodology to calculate the valence electron affinities of temporary anions. Phys Chem Chem Phys 2009; 11:9013-24. [DOI: 10.1039/b908870a] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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22
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Puiatti M, Vera DMA, Pierini AB. Species with negative electron affinity and standard DFT methods. Finding the valence anions. Phys Chem Chem Phys 2008; 10:1394-9. [PMID: 18309394 DOI: 10.1039/b716625g] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently, we have shown that traditional bound-electron DFT models are reliable enough to reproduce negative electron affinities (EA) within a few meV, as long as the valence anion state is found, but they seem to fail in predicting the lowest EA when the ground anion state obtained is non-valence, which holds the extra electron in a diffuse orbital around the molecule; here we propose an alternative approach for finding the valence anion state, based on the stabilization exerted by a polar solvent; the methodology yields correct EA values (i.e. beyond the Koopman's theorem approximation) by gradually decreasing the dielectric constant of the medium.
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Affiliation(s)
- Marcelo Puiatti
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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Simona F, Magistrato A, Vera DMA, Garau G, Vila AJ, Carloni P. Protonation state and substrate binding to B2 metallo-beta-lactamase CphA from Aeromonas hydrofila. Proteins 2007; 69:595-605. [PMID: 17623844 DOI: 10.1002/prot.21476] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The zinc enzymes metallo beta-lactamases counteract the beneficial action of beta-lactam antibiotics against bacterial infections, by hydrolyzing their beta-lactam rings. To understand structure/function relationships on a representative member of this class, the B2 M beta L CphA, we have investigated the H-bond pattern at the Zn enzymatic active site and substrate binding mode by molecular simulation methods. Extensive QM calculations at the DFT-BLYP level on eleven models of the protein active site, along with MD simulations of the protein in aqueous solution, allow us to propose two plausible protonation states for the unbound enzyme, which are probably in equilibrium. Docking procedures along with MD simulations and QM calculations suggest that in the complex between the enzyme and its substrate (biapenem), the latter is stable in only one of the two protonation states, in addition it exhibits two different binding modes, of which only one agrees with previous proposals. In both cases, the substrate is polarized as in aqueous solution. We conclude that addressing mechanistic issues on this class of enzymes requires a careful procedure to assign protonation states and substrate docking modes.
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Affiliation(s)
- F Simona
- SISSA, Via Beirut 2-4, 34014 Grignano, Trieste, Italy
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Grosso V, Previtali C, Chesta CA, Vera DMA, Pierini AB. An experimental and theoretical study on the electrostatic effect of an appended cationic group on electronic properties of aromatic systems. Phys Chem Chem Phys 2007; 9:5988-96. [DOI: 10.1039/b709751d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The anionic surfaces of the 1-chloro- and 4-chlorobicyclo[2.2.1]heptan-2-one, 1-chloro- and 4-chlorobicyclo[2.2.2]octan-2-one, 1-chloro- and 5-chloroadamantan-2-one, and 2-chlorotricyclo[7.3.1.0(2,7)]tridecan-13-one were explored using DFT functionals with full geometry optimization in solution. The reductive cleavage of these compounds is controlled by the rigidity of the polycycle, its capability to form an unstrained radical, and by the relative carbonyl/C-Cl disposition on the bridge. Such control can be exerted by either a concerted-dissociative or a stepwise mechanism with radical anions as intermediates. 5-Chloroadamantan-2-one is the most suitable compound to follow the latter pathway.
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Affiliation(s)
- Jorge G Uranga
- INFIQC - Departamento de Química Organica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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26
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Vera DMA, Pierini AB. Species with negative electron affinity and standard DFT methodsElectronic supplementary information (ESI) available: (i) Details of calculations (total energies, zero point corrections, etc.) and correlations obtained with different basis sets. (ii) Color graphics: structure, dipole, SOMO diagram and spin densities. (iii) xyz coordinates of all species. See http://www.rsc.org/suppdata/cp/b4/b403898c/. Phys Chem Chem Phys 2004. [DOI: 10.1039/b403898c] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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27
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Pierini AB, Santiago AN, Allende SG, Vera DMA. Electron transfer reactions to 1-adamantyl-, 1-norbornyl chlorides, and their oxo derivatives. A theoretical study. ARKIVOC 2003. [DOI: 10.3998/ark.5550190.0004.a44] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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28
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Abstract
The potential energy surfaces for the fragmentation of the radical anions of p-nitrochlorobenzene and p- and m-chloroacetophenones were explored using first principle methods. The behavior of these compounds, stabilized by pi acceptors, is compared to that shown by the unsubstituted halobenzenes (PhX, X = F, Cl, Br, I). The presence of pi and sigma radical anions was inspected as well as the intramolecular electron transfer (intra-ET) from the pi to the sigma surface, responsible for the dissociation of these intermediates. The profiles obtained with the B3LYP functional in the gas phase and in the presence of a polar solvent are in agreement with the spectroscopic evidence and with the experimentally observed reactivity of the compounds under study. The stability of the radical anion of p-nitrochlorobenzene and the adiabatic and endothermic nature of its dissociation are explained. The order of the rate constants for dissociation m-chloroacetophenone < p-chloroacetophenone is interpreted on the basis of the differences in the adiabatic character of the intra-ET of both isomers which is ascribed to the nodal properties of their SOMOs. In the halobenzene family, the electronic factors responsible for the intra-ET are analyzed. The stabilization of the sigma surface exerted by the different halogens and its effect on the rate constants for dissociation are explained.
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Affiliation(s)
- Adriana B Pierini
- INFIQC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, 5000 Córdoba, Argentina.
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