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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

A Supramolecular Interaction of a Ruthenium Complex With Calf-Thymus DNA: A Ligand Binding Approach by NMR Spectroscopy

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Crizostomo Kock, Flavio Vinicius [1] ; Costa, Analu Rocha [2] ; de Oliveira, Katia Mara [2] ; Batista, Alzir Azevedo [2] ; Ferreira, Antonio Gilberto [1] ; Venancio, Tiago [1]
Total Authors: 6
[1] Univ Fed Sao Carlos, Dept Chem, Lab Nucl Magnet Resonance, Sao Carlos, SP - Brazil
[2] Univ Fed Sao Carlos, Lab Struct & React Inorgan Cpds, Dept Chem, Sao Carlos, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: FRONTIERS IN CHEMISTRY; v. 7, NOV 8 2019.
Web of Science Citations: 0

Lawsone itself exhibits interesting biological activities, and its complexation with a metal center can improve the potency. In this context a cytotoxic Ru-complex, {[}Ru(law)(dppb)(bipy)] (law = lawsone, dppb = 1,4-bis(diphenylphosphino)butane and bipy = 2,2 `-bipyridine), named as CBLAU, was prepared as reported. In this work, NMR binding-target studies were performed to bring to light the most accessible interaction sites of this Ru-complex toward Calf-Thymus DNA (CT-DNA, used as a model), in a similar approach used for other metallic complexes with anti-cancer activity, such as cisplatin and carboplatin. Advanced and robust NMR binding-target studies, among them Saturation Transfer Difference (STD)-NMR and longitudinal relaxometry (T-1), were explored. The H-1 and P-31 -NMR data indicate that the structure of Ru-complex remains preserved in the presence of CT-DNA, and some linewidth broadening is also observed for all the signals, pointing out some interaction. Looking at the binding efficiency, the T-1 values are highly influenced by the formation of the CBLAU-DNA adduct, decreasing from 11.4 s (without DNA) to 1.4 s (with DNA), where the difference is bigger for the lawsone protons. Besides, the STD-NMR titration experiments revealed a stronger interaction (K-D = 5.9 mM) for CBLAU-DNA in comparison to non-complexed lawsone-DNA (K-D = 34.0 mM). The epitope map, obtained by STD-NMR, shows that aromatic protons from the complexed lawsone exhibits higher saturation transfer, in comparison to other Ru-ligands (DPPB and bipy), suggesting the supramolecular contact with CT-DNA takes place by the lawsone face of the Ru-complex, possibly by a spatial pi-pi stacking involving pi-bonds on nucleic acids segments of the DNA chain and the naphthoquinone group. (AU)

FAPESP's process: 18/09145-5 - Characterization of supramolecular complexes by solution and solid state high resolution nuclear magnetic resonance
Grantee:Tiago Venancio
Support type: Regular Research Grants
FAPESP's process: 18/16040-5 - Biorational control of Pest-Insect
Grantee:Flavio Vinicius Crizostomo Kock
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 18/19342-2 - Metal complexes with dirivative ligands of lawsone and acylthioureas, with anticancer potential activities: study in vitro and in vivo
Grantee:Alzir Azevedo Batista
Support type: Regular Research Grants