Molecular docking, QSAR properties and DNA/BSA binding, anti-proliferative studies of 6-methoxy benzothiozole imine base and its metal complexes

Application of Novel Ruthenium (II) Polypyridyl Complexes as Robust DNA Probes, Optical Material and Antimicrobials-An Experimental and DFT Approach

The nature of the interaction of DNA with heteroleptic Ruthenium (II) Polypyridyl complexes of the type [Ru (A)2TPIP]2+, where TPIP = 2-(1-p-tolyl-1H pyrazol-4 -yl)-1H-imidazo [4, 5-f[1. 10] phenanthroline and A = 1,10 phenanthroline (1),4,4'-dimethyl-1,10-ortho Phenanthroline (2), 2,2' - bipyridine (3) and 4, 4' dimethyl 2, 2'- bipyridine (4), has been investigated by experimentaland molecular docking approaches. The order of the DNA binding affinities of the synthesised complexes is 1 > 2 > 3 > 4. The findings imply that the unsubstituted complex has a better affinity to bind with DNA than the substituted (dmp and dmb) emphasizing the significance of the auxiliary ligand. Additionally, as the medium's ionic strength drops, the DNA/Ru ratio rises, or when water is displaced by glycerol, the intercalation of complexes into DNA increases. DFT calculations at the B3LYP/LANL2MB level was used for molecular geometry (Ground State) and electronic characteristic calculations. The HOMO-LUMO gap of the Ru [II] complex is less than the intercalator and hence kinetically labile. Among the complexes, the bpy complex has shown utmost non-linear optical properties (α = -153.9099 10-24esu and β = 3.8498 10-30esu). The docking study shows the significance of the Metal-intercalator's shorter length may increase DNA binding affinity. This study divulges that the Ruthenium (II) polypyridyl complexes bind to DNA preponderantly by intercalation supporting Viscosity studies. All the complexes have a considerable attraction for guanine. The standard disk diffusion method reveals that complexes (1, 2, 3 and 4) have good antibacterial activity.

Insights into the interaction of azinphos-methyl with bovine serum albumin: experimental and molecular docking studies

In the present study, combining spectroscopic and molecular modeling techniques has been used to analyze azinphos-methyl binding properties, as an organophosphorus pesticide, to bovine serum albumin. The quenching interaction of azinphos-methyl with bovine serum albumin was investigated in an appropriate physiological state (pH = 7.4). Fluorescence spectroscopy, UV-visible spectroscopy, circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR). Findings showed differences in the secondary protein structure microenvironment following interaction with azinphos-methyl. The results from spectroscopic experiments suggest that azinphos-methyl binds to bovine serum albumin residues with a binding constant in the range of 0.099 × 10⁵-0.209 × 10⁵ M^-1 in one binding site (Tyr 160). The experimental results are supported by computational techniques such as docking using a bovine serum albumin crystal model. The results show that azinphos-methyl is linked to the site I of bovine serum albumin (in subdomain IB), and the result was in accordance with the experimental result. Based on the negative ΔG°, ΔH° and ΔS° values, the binding between azinphos-methyl and bovine serum albumin was spontaneous, and docking studies confirmed hydrogen bonding and van der Waals forces between them.Communicated by Ramaswamy H. Sarma.

Visible-Light-Prompted Synthesis and Binding Studies of 5,6-Dihydroimidazo[2,1-b]thiazoles with BSA and DNA Using Biophysical and Computational Methods

Fused heterocyclic systems containing a bridgehead nitrogen atom have emerged as imperative pharmacophores in the design and development of new drugs. Among these heterocyclic moieties, the imidazothiazole scaffold has long been used in medicinal chemistry for the treatment of various diseases. In this study, we have established a simplistic and environmentally safe regioselective protocol for the synthesis of 5,6-dihydroimidazo[2,1-b]thiazole derivatives from easily available reactants. The reaction proceeds through in situ formation of the α-bromodiketones ensuing trap with imidazolidine-2-thione to provide these versatile bicyclic heterocycles in excellent yields. The synthesized compounds were screened through the molecular docking approach for the most stable complex formation with bovine serum albumin (BSA) and calf thymus deoxyribonucleic acid (ctDNA). The selected compound was further studied using ex vivo binding studies, which revealed moderate interactions with BSA and ctDNA. The binding studies were performed using biophysical approaches including UV-visible spectroscopy, steady-state fluorescence, circular dichroism (CD), and viscosity parameters.

Evaluation of biomolecular interactions and cytotoxic activity of organometallic binuclear Ru(II) complexes of ferrocenyl thiosemicarbazones

Four new ferrocenyl substituted thiosemicarbazone ligands (L1-L4) and their corresponding binuclear ruthenium(II) arene complexes of the general type [(η⁶-p cym)(L)Ru(μ-im)Ru(L)(η⁶-p-cym)]Cl (C1-C4) and [(η⁶-p cym)(L)Ru(μ-azpy)Ru(L)(η⁶-p-cym)]Cl₂ (C5-C8) (cym = cymene, im = imidazole, azpy = 4,4'-azopyridine) have been synthesized and characterized. The structures of the complexes were established through DFT calculations and geometry optimization. The interactions of the binuclear complexes with DNA were investigated by absorption, emission and viscosity studies which indicated that the complexes bind to DNA via intercalation. Meanwhile, the interaction of complexes with the protein, bovine serum albumin (BSA), has also been studied using fluorescence emission spectroscopy. The experimental results show that the binuclear complexes exhibit good binding propensities to BSA. The complexes can quench the intrinsic fluorescence of BSA remarkably through a static or dynamic quenching process. In addition, the in vitro cytotoxicity of complexes C1-C8 against HeLa cell line was assayed which showed lower IC₅₀ values indicating their higher cytotoxicity and potency in killing the cancer cells at low concentrations.Communicated by Ramaswamy H. Sarma.