scholarly journals DNA-Based Electrodes and Computational Approaches on the Intercalation Study of Antitumoral Drugs

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7623
Author(s):  
Edson Silvio Batista Rodrigues ◽  
Isaac Yves Lopes de Macêdo ◽  
Giovanna Nascimento de Mello e Silva ◽  
Arthur de Carvalho e Silva ◽  
Henric Pietro Vicente Gil ◽  
...  

The binding between anticancer drugs and double-stranded DNA (dsDNA) is a key issue to understand their mechanism of action, and many chemical methods have been explored on this task. Molecular docking techniques successfully predict the affinity of small molecules into the DNA binding sites. In turn, various DNA-targeted drugs are electroactive; in this regard, their electrochemical behavior may change according to the nature and strength of interaction with DNA. A carbon paste electrode (CPE) modified with calf thymus ds-DNA (CPDE) and computational methods were used to evaluate the drug–DNA intercalation of doxorubicin (DOX), daunorubicin (DAU), idarubicin (IDA), dacarbazine (DAR), mitoxantrone (MIT), and methotrexate (MTX), aiming to evaluate eventual correlations. CPE and CPDE were immersed in pH 7 0.1 mM solutions of each drug with different incubation times. As expected, the CPDE response for all DNA-targeted drugs was higher than that of CPE, evidencing the drug–DNA interaction. A peak current increase of up to 10-fold was observed; the lowest increase was seen for MTX, and the highest increase for MIT. Although this increase in the sensitivity is certainly tied to preconcentration effects of DNA, the data did not agree entirely with docking studies, evidencing the participation of other factors, such as viscosity, interfacial electrostatic interactions, and coefficient of diffusion.

Author(s):  
Cleiton M. da Silva ◽  
Marina M. Silva ◽  
Fabiano S. Reis ◽  
Ana Lúcia T.G. Ruiz ◽  
João E. de Carvalho ◽  
...  

The applicability of the novel cyanine dye AK 3-1 to the detection and characterization of pathogenic protein aggregates, amyloid fibrils, was tested using the absorption spectroscopy technique. In an organic solvent dimethyl sulfoxide (DMSO), absorption spectra of AK3-1 exhibits vibrational structure with the relative intensity of 0-0 sub-band being higher than that for the 0-1 sub-band. In an aqueous phase the dye absorption band undergoes hypsochromic shift relative to DMSO due to H-aggregation of the dye. The interaction of AK3-1 with the native and fibrillar insulin was followed by the decrease of monomer band and the enhancement of H-dimer band. To evaluate the relative contributions of the monomeric and aggregated forms, the absorption spectra of the protein-bound dye were deconvoluted using the asymmetric log-normal (LN) function. The analysis of the set of fitting parameters provides evidence for the protein-induced AK3-1 self-association into the head-to-head dimers, with the magnitude of this effect being much more pronounced for fibrillar protein form. The molecular docking studies showed that the AK3-1 monomer tends to associate with the specific arrangement of side chains in the β-sheet formed by L17 leucine residues (of the insulin B-chain), located on the dry steric zipper interface of the fibril, while the dye dimers form stable complexes with the amyloid groove formed by the residues Q15 and E17 of the A-chain, and located on the wet interface of the fibril. The latter binding site is more easily accessible and is additionally stabilized by the electrostatic interactions between the positively charged dye and the E17 residue. This binding mode seems to be prevailing over that for the AK3-1 monomers. Based on the results obtained, AK3-1 may be recommended as a prospective amyloid marker complementary to the classical amyloid reporters Thioflavin T and Congo Red.


RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 63549-63558 ◽  
Author(s):  
Saptarshi Ghosh ◽  
Pronab Kundu ◽  
Bijan Kumar Paul ◽  
Nitin Chattopadhyay

Binding mode of biologically relevant anionic probe, ANS, with ctDNA is divulged from spectroscopic and molecular docking studies.


2016 ◽  
Vol 1107 ◽  
pp. 99-108 ◽  
Author(s):  
Shahzad Murtaza ◽  
Saima Shamim ◽  
Naghmana Kousar ◽  
Muhammad Nawaz Tahir ◽  
Muhammad Sirajuddin ◽  
...  

Processes ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 13
Author(s):  
Khairulazhar Jumbri ◽  
Mohd Azlan Kassim ◽  
Normawati M. Yunus ◽  
Mohd Basyaruddin Abdul Rahman ◽  
Haslina Ahmad ◽  
...  

This work presents a molecular level investigation on the nature and mode of binding between imidazolium-based ionic liquids (ILs) ([Cnbim]Br where n = 2, 4, 6) with calf thymus DNA. This investigation offers valuable insight into the mechanisms of interactions that can affect the structural features of DNA and possibly cause the alteration or inhibition of DNA function. To expedite analysis, the study resorted to using molecular docking and COnductor like Screening MOdel for Real Solvents (COSMO-RS) in conjunction with fluorescence spectroscopic data for confirmation and validation of computational results. Both the fluorescence and docking studies consistently revealed a weak interaction between the two molecules, which corresponded to the binding energy of a stable docking conformation in the range of −5.19 to −7.75 kcal mol−1. As predicted, the rod-like structure of imidazolium-based ILs prefers to bind to the double-helix DNA through a minor groove. Interestingly, the occurrence of T-shape π-π stacking was observed between the amine group in adenine that faces the aromatic ring of imidazole. In addition, data of COSMO-RS for the interaction of individual nucleic acid bases to imidazolium-based ILs affirmed that ILs showed a propensity to bind to different bases, the highest being guanine followed by cytosine, thymine, uracil, and adenine.


Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4519 ◽  
Author(s):  
Jiahe Li ◽  
Rongping Liu ◽  
Jinzhang Jiang ◽  
Xing Liang ◽  
Ling Huang ◽  
...  

A series of ZnCl2 complexes (compounds 1–10) with 4′-(substituted-phenyl)-2,2′:6′,2′′-terpyridine that bears hydrogen (L1), p-methyl (L2), p-methoxy (L3), p-phenyl (L4), p-tolyl (L5), p-hydroxyl (L6), m-hydroxyl (L7), o-hydroxyl (L8), p-carboxyl (L9), or p-methylsulfonyl (L10) were prepared and then characterized by 1H NMR, electrospray mass-spectra (ESI-MS), IR, elemental analysis, and single crystal X-ray diffraction. In vitro cytotoxicity assay was used to monitor the antiproliferative activities against tumor cells. Absorption spectroscopy, fluorescence titration, circular dichroism spectroscopy, and molecular modeling studied the DNA interactions. All of the compounds display interesting photoluminescent properties and different maximal emission peaks due to the difference of the substituent groups. The cell viability studies indicate that the compounds have excellent antiproliferative activity against four human carcinoma cell lines, A549, Bel-7402, MCF-7, and Eca-109, with the lowest IC50 values of 0.33 (10), 0.66 (6), 0.37 (7), and 1.05 (7) μM, respectively. The spectrophotometric results reveal that the compounds have strong affinity binding with DNA as intercalator and induce DNA conformational transition. Molecular docking studies indicate that the binding is contributed by the π…π stacking and hydrogen bonds, providing an order of nucleotide sequence binding selectivity as ATGC > ATAT > GCGC. These compounds intercalate into the base pairs of the DNA of the tumor cells to affect their replication and transcription, and the process is supposed to play an important role in the anticancer mechanism.


2019 ◽  
Vol 47 (20) ◽  
pp. 10830-10841 ◽  
Author(s):  
Marc Laforet ◽  
Thomas A McMurrough ◽  
Michael Vu ◽  
Christopher M Brown ◽  
Kun Zhang ◽  
...  

Abstract Identifying and validating intermolecular covariation between proteins and their DNA-binding sites can provide insights into mechanisms that regulate selectivity and starting points for engineering new specificity. LAGLIDADG homing endonucleases (meganucleases) can be engineered to bind non-native target sites for gene-editing applications, but not all redesigns successfully reprogram specificity. To gain a global overview of residues that influence meganuclease specificity, we used information theory to identify protein–DNA covariation. Directed evolution experiments of one predicted pair, 227/+3, revealed variants with surprising shifts in I-OnuI substrate preference at the central 4 bases where cleavage occurs. Structural studies showed significant remodeling distant from the covarying position, including restructuring of an inter-hairpin loop, DNA distortions near the scissile phosphates, and new base-specific contacts. Our findings are consistent with a model whereby the functional impacts of covariation can be indirectly propagated to neighboring residues outside of direct contact range, allowing meganucleases to adapt to target site variation and indirectly expand the sequence space accessible for cleavage. We suggest that some engineered meganucleases may have unexpected cleavage profiles that were not rationally incorporated during the design process.


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