DNA Binding and Photocleavage Studies of Cobalt(III) Polypyridine Complexes: [Co(en)2PIP]3+, [Co(en)2IP]3+, and [Co(en)2phen-dione]3+

In this paper, three complexes of type [Co(en)2PIP]3+(PIP=2-phenylimidazo[4,5-f][1,10,] phenanthroline)(1), [Co(en)2IP]3+ (IP = imidazo[4,5-f][1,10,] phenanthroline)(2), and [Co(en)2phen-dione]3+(1,10 phenanthroline 5,6,dione)(3) have been synthesized and characterized by UV/VIS, IR, 1H NMR spectral methods. Absorption spectroscopy, emission spectroscopy, viscosity measurements, and DNA melting techniques have been used for investigating the binding of these two complexes with calf thymus DNA, and photocleavage studies were used for investigating these binding of these complexes with plasmid DNA. The spectroscopic studies together with viscosity measurements and DNA melting studies support that complexes 1 and 2 bind to CT DNA (= calf thymus DNA) by intercalation mode via IP or PIP into the base pairs of DNA, and complex 3 is binding as groove mode. Complex 1 binds more avidly to CT DNA than 2 and 3 which is consistent with the extended planar ring π system of PIP. Noticeably, the two complexes have been found to be efficient photosensitisers for strand scissions in plasmid DNA

Efficient and region-selective conversion of octanes to epoxides under ambient conditions: Performance of tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz)

742-745In this paper, is described the conversion of the octane group of hydrocarbons into industrially important epoxides using tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz). The role of hydrogen peroxide as a sacrificial oxygen donor during catalytic conversion to epoxides has been investigated. The performance of the catalyst has been evaluated in terms of turnover numbers (TON) and turnover frequencies (TOF) reported in this article

Efficient and region-selective conversion of octanes to epoxides under ambient conditions: Performance of tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz)

In this paper, is described the conversion of the octane group of hydrocarbons into industrially important epoxides using tri-copper catalyst, [Cu3I(L)]+1 (L=7-N-Etppz). The role of hydrogen peroxide as a sacrificial oxygen donor during catalytic conversion to epoxides has been investigated. The performance of the catalyst has been evaluated in terms of turnover numbers (TON) and turnover frequencies (TOF) reported in this article.

DNA Binding and Photocleavage Studies of Cobalt(III) Ethylenediamine Pyridine Complexes: [Co(en)2(py)2]3+ and [Co(en)2(mepy)2]3+

Two novel cobalt(III) pyridine complexes (1) [Co(en)2(py)2]3+ and (2) [Co(en)2(mepy)2]3+ (en=ethylenediamine, py=pyridine, and mepy=methylpyridine) have been synthesized and characterized. The interaction of these complexes with calf thymus DNA was investigated by absorption, emission spectroscopy, viscosity measurements, DNA melting, and DNA photocleavage. Results suggest that the two complexes bind to DNA via groove mode and complex 2 binds more strongly to CT DNA than complex 1. Moreover, these Co(III) complexes have been found to promote the photocleavage of plasmid DNA pBR322 under irradiation at 365 nm, cytotoxicity results of complexes are also showing anticancer activity

CT-DNA-binding and biological activity of mononuclear copper(II) complexes with imidazo-phenanthroline ligands

37-44Four imidazo-phenanthroline (IP) based ligands and its corresponding copper polypyridyl complexes have been prepared [Cu(L1-L4)2]2+ and characterized by various physicochemical techniques. Herein we are reporting the CT-DNA (calf-thymus DNA) binding & anti-cancer affinity of ligands (L1-L4) as well as complexes (C1-C4). The DNA binding affinity of synthesized C1-C4 has been carried out by using spectroscopic techniques like UV/visible, emission, molecular modeling and viscosity techniques. The obtained results are clearly indicating that all C1-C4 complexes bind to DNA via intercalative mode and they possess a significant cytotoxic effect toward selected cancer cell lines (MDA-MB-231, B16-F10, DU-145 and CHO-K1)

CT-DNA-binding and biological activity of mononuclear copper(II) complexes with imidazo-phenanthroline ligands

Four imidazo-phenanthroline (IP) based ligands and its corresponding copper polypyridyl complexes have been prepared [Cu(L1-L4)2]2+ and characterized by various physicochemical techniques. Herein we are reporting the CT-DNA (calf-thymus DNA) binding & anti-cancer affinity of ligands (L1-L4) as well as complexes (C1-C4). The DNA binding affinity of synthesized C1-C4 has been carried out by using spectroscopic techniques like UV/visible, emission, molecular modeling and viscosity techniques. The obtained results are clearly indicating that all C1-C4 complexes bind to DNA via intercalative mode and they possess a significant cytotoxic effect toward selected cancer cell lines (MDA-MB-231, B16-F10, DU-145 and CHO-K1)

Inactivation of the particulate methane monooxygenase (pMMO) in Methylococcus capsulatus (Bath) by acetylene

Acetylene (HCCH) has a long history as a mechanism-based enzyme inhibitor and is considered an active-site probe of the particulate methane monooxygenase (pMMO). Here, we report how HCCH inactivates pMMO in Methylococcus capsulatus (Bath) by using high-resolution mass spectrometry and computational simulation. High-resolution MALDI-TOF MS of intact pMMO complexes has allowed us to confirm that the enzyme oxidizes HCCH to the ketene (C_2H_2O) intermediate, which then forms an acetylation adduct with the transmembrane PmoC subunit. LC-MS/MS analysis of the peptides derived from in-gel proteolytic digestion of the protein subunit identifies K196 of PmoC as the site of acetylation. No evidence is obtained for chemical modification of the PmoA or PmoB subunit. The inactivation of pMMO by a single adduct in the transmembrane PmoC domain is intriguing given the complexity of the structural fold of this large membrane-protein complex as well as the complicated roles played by the various metal cofactors in the enzyme catalysis. Computational studies suggest that the entry of hydrophobic substrates to, and migration of products from, the catalytic site of pMMO is controlled tightly within the transmembrane domain. Support of these conclusions is provided by parallel experiments with two related alkynes: propyne (CH3CCH) and trifluoropropyne (CF_3CCH). Finally, we discuss the implication of these findings to the location of the catalytic site in pMMO

Kinetics and binding studies on the reaction of cyanopropyl(aquo)cobaloxime with CT-DNA and amines

2628-2631The ligand substitution reactions of cyanopropyl (aquo) cobaloxime have been studied with various amines such as Methylamine, ethylamine, butylamine, pentylamine, hexylamine, cyclopropylamine, cyclohexylamine and cyclope ntylamine, as entering nucleophiles. The entering nucleophile displaces the molecule trans to the cyanopropyl group to form the six-coordinated complex, [CNCH2CH2 CH2Co(DH)2L]. The rate constants have been determined by varying the pH and concentration of the ligand under pseudo first order conditions. Equilibrium constants have been determined as a function of pH, for the binding of amines to [CNCH2CH2 CH2Co(DH)2L]. Study shows that the entering nucleophile participates in the transition state, and hence, SN1 mechanism is proposed. Antimicrobial activity of cyanopropyl (aquo)cobaloxime on E coli has been studied. The interaction of cyanopropyl(aquo) cobaloxime with CT DNA has been studied spectrophotometrically and binding constant has been calculated

Recent Advances in Copper Intercalators as Anticancer Agents

anticancer drugs and presently, many studies are being pursued worldwide on the development of copper-based complexes as potential anticancer drugs. Herein, we briefly discuss the importance of reactive oxygen species in biological applications and copper(II) complexes as anticancer drugs. The anti-angiogenic properties of mono-nuclear copper(II) complexes have been demonstrated by in vivo chick embryo angiogenesis analysis. The plausible mechanism behind anticancer activity of these complexes is by the formation of excessive intracellular Reactive Oxygen Species (ROS). ROS is a composite term used for oxygen derivative non-radicals and free radicals of highly reactive components, that enhances the killing response of immune cells to microbial invasion. Previous reports have shown that ROS plays an important role as a messenger in cell cycling and normal cell signal transduction

Plasmonics driven engineered pasteurizers for solar water disinfection (SWADIS)

Rampant environmental pollution is the most ubiquitous concern of current world. A sustainable panacea to overarching contamination of water-borne pathogens demands cheap and eco-friendly oriented research. Solar energy is effortlessly accessible in most of the weather conditions and can be used for water decontamination. In this context, Solar Water Disinfection (SWADIS) appears to be feasible solution. Herein we are reporting newly developed Carbon nanoparticles (CNP) which shows absorption of light in broad region extending from Ultraviolet–Visible (UV) to Infrared Spectroscopy (IR). This CNP with pronounced photothermal effect has been used for SWADIS. Photothermal effect of plasmonic nanomaterials has massive potential and has exploited for disinfection of water. Moving towards practical device design we have developed an efficient CNP based Multipurpose Solar Pasteurizer (MSP) and Nano-Solar Pasteurizer (NSP) which can efficiently perform the SWADIS. Result shows that upon irradiation under natural solar radiation pasteurizers can thermally inactivate the bacteria. The system proves to be able to perform 100% bacterial inactivation in sunny days. We also conducted bacterial inactivation experiments by simulating 106 CFU mL−1 concentration of E. coli in water to mimic field conditions. Results are evident that pasteurizers achieved 100% bacterial inactivation within period of ˜45 min under sunlight