Zinc(II) complexes of carboxamide derivatives: Crystal structures and interaction with calf thymus DNA

Two mononuclear zinc(II) complexes of newly designed carboxamide derivatives, formulated as [Zn(L1)3](ClO4)2 (1) and [Zn(L2)3](ClO4)2 (2) [where L1 = N-(furan-2-ylmethyl)-2-pyridinecarboxamide and L2 = N-(thiophen-2-ylmethyl)-2-pyridine-carboxamide], have been isolated in pure form in the reaction of perchlorate salts of Zn(II) with ligands L1 and L2, respectively. The two complexes were characterized by physicochemical and spectroscopic tools, and by X-ray crystal structures of both ligands and the complex 1. In complex 1, zinc(II) is chelated by three ligands with a distorted octahedral geometry. The DNA-binding properties of zinc complexes 1 and 2 have been investigated by spectroscopic methods and viscosity measurements. The results suggest that both complexes 1 and 2 bind to DNA in an intercalation mode between the uncoordinated furan or thiophene chromophore and the base pairs of DNA

Synthesis and characterization of a new water-soluble non-cytotoxic mito-tracker capped silicon quantum dot

19-25Allyl triphenylphosphonium bromide based mito-tracker capped silicon quantum dot (Mito-SiQDs) has been synthesized through an inverse micelle process. It was then fully characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering techniques and X-ray photoelectron spectroscopic method. Energy dispersive X-ray spectroscopy analyses of the quantum dots confirm the presence of carbon, silicon, phosphorous and bromine atoms in Mito-SiQDs. Morphological study by transmission electron microscopy experiment showed the formation of the particles of size 11-12 nm of quantum dot dimension. The high negative zeta potential value of –23.7 mV calculated from dynamic light scattering study indicates the high stability of the circumvent agglomeration of Mito-SiQDs. The mito-tracker capped silicon quantum dot has blue emission at 400 nm wavelength upon excitation at 327 nm. Mito-SiQDs has not shown any significant cytotoxic effect with 10 to 50 μL/mL concentration on HeLa cell line for at least up to 12 h of its treatment. The Mito-SiQDs would be useful a possible fluorescent marker to visualize mitochondrial subcellular compartment in living cell through fluorescence imaging study

<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-US;mso-fareast-language:EN-US;mso-bidi-language:AR-SA" lang="EN-US">Estimation of Fe(III) using ⁵⁹Fe and acetylacetone by substoichiometric isotope -dilution analysis</span>

357-360A highly precise and rapid method for the quantitative estimation of iron traces by substoichiometric isotope dilution analysis has been described. The method involves the extraction of spiked (59Fe) iron(III) with substoichiometric amounts of acetylacetone into chloroform at pH 2.0. The proposed method is free from interferences of various closely related foreign ions, thereby establishing the selectivity of the proposed technique. The present method has also been applied to different certified alloys without any pre-separation and the trace quantities of iron are successfully evaluated

A dysprosium-based metal-organic framework: Synthesis, characterization, crystal structure and interaction with calf thymus-DNA and bovine serum albumin

A dysprosium-based metallo-organic framework (MOF) containing calcium ions formulated as {Dy(pyda)3Ca1.5(H2O)6} \ub7 5.5H2O (1) (H2pyda = pyridine-2,6-dicarboxylic acid) was solvothermally synthesized in ethanolic medium and characterized by physico-chemical and spectroscopic tools. A detailed structural analysis of the solid state structure of 1 by single crystal X-ray diffraction study showed a tricapped trigonal prism geometry for lanthanide in the [Dy(pyda)3]3 12 fragment. The mode of interaction of 1 with calf thymus- DNA and with protein bovine serum albumin (BSA) was investigated by using absorption and emission spectroscopic tools. The apparent association constant of complex 1 with CT-DNA was deduced from an absorption spectral study (Kb = 4.08 7 104 M 121). Spectral and viscosity measurements indicated a groove-binding mode of 1 with CT-DNA, and from spectroscopic study the formation of a metal complex-BSA adduct was assumed to be the result of the interaction of 1 with BSA

Palladium (II) and platinum (II) complexes of deprotonated N, N´-bis (2-pyridinecarboxamide)-1, 2-benzene: synthesis, structural characterization and binding interactions with DNA and BSA

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Interaction of KMP-11 with Phospholipid Membranes and Its Implications in Leishmaniasis: Effects of Single Tryptophan Mutations and Cholesterol

KMP-11 is a small protein that is believed to control the overall bilayer pressure of the Leishmania parasite.Recent results have suggested that membrane binding and the presence of cholesterol affect the efficacy of Leishmanial infection, in which KMP-11 plays an important role. Nevertheless, there exists no systematic study of membrane interaction with KMP-11 either in the absence or presence of cholesterol. In this article, we investigated the interaction between KMP-11 and phospholipid membranes using an unsaturated (PC 18:1; 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)) and saturated (PC 12:0; 1,2-dilauroyl-snglycero- 3-phosphocholine (DLPC)) lipid as membrane mimics. Additionally, we studied the effect of cholesterol on the protein−membrane interaction. Steady-state as well as timeresolved fluorescence spectroscopy, isothermal titration calorimetry (ITC), and ζ-potential measurements were used for the determination of the binding constants for the wild-type (WT) and single-site tryptophan mutants. Single-site tryptophan mutants were designed to make sure that the tryptophan residues sample different surface exposures in different mutants. In the absence of cholesterol, the membrane-binding affinities of the partially exposed and buried tryptophan mutants (Y5W and Y48W, respectively) were found to be greater than those of the WT protein. In the presence of cholesterol, the binding constants of the WT and Y48W mutant were found to decrease with an increase in cholesterol concentration. This was in contrast to that in the Y5W and F77W mutants, in which the binding constants increased on adding cholesterol. The present study highlights the interplay among the conformational architecture of a protein, its interaction with the membrane, and membrane composition in modulating the survival of a Leishmania parasite inside host macrophages

A ratiometric fluorescent chemosensor for iron: discrimination of Fe2+ and Fe3+ and living cell application

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