scholarly journals Crystal structure of the inclusion complex of cholesterol in β-cyclodextrin and molecular dynamics studies

2018 ◽  
Vol 14 ◽  
pp. 838-848 ◽  
Author(s):  
Elias Christoforides ◽  
Andreas Papaioannou ◽  
Kostas Bethanis
Keyword(s):  
Crystal Structure ◽  
Inclusion Complex ◽  
Mammalian Cells ◽  
Inclusion Compound ◽  
Physicochemical Characterization ◽  
Md Simulations ◽  
Cholesterol Removal ◽  
Triclinic Space Group

The role of beta-cyclodextrin (β-CD) in cholesterol removal primarily from mammalian cells and secondly from dairy products has been studied thoroughly in recent years. Although the physicochemical characterization of the inclusion compound of cholesterol in β-CD has been achieved by various methods, no crystal structure has been determined so far. We report here the crystal structure of the inclusion compound of cholesterol in β-CD. The inclusion complex crystallizes in the triclinic space group P1 forming head-to-head dimers which are stacked along the c-axis. One well-defined cholesterol molecule ‘axially’ encapsulated inside the β-CD dimer and 22 water molecules that stabilize the complexes in the crystalline state comprise the asymmetric unit of the structure. The dimers are arranged in an intermediate (IM) channel packing mode in the crystal. Moreover, MD simulations, at 300 and 340 K, based on the crystallographically determined coordinates of the complex show that the formed cholesterol/β-CD inclusion compound remains very stable in aqueous solution at both temperatures.

Structural and IR-spectroscopic characterization of magnesium acesulfamate

2016 ◽  
Vol 71 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Oscar E. Piro ◽  
Gustavo A. Echeverría ◽  
Beatriz S. Parajón-Costa ◽  
Enrique J. Baran
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Elemental Analysis ◽  
Spectroscopic Characterization ◽  
Magnesium Carbonate ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Ir Spectroscopic

AbstractMagnesium acesulfamate, Mg(C4H4NO4S)2·6H2O, was prepared by the reaction of acesulfamic acid and magnesium carbonate in aqueous solution, and characterized by elemental analysis. Its crystal structure was determined by single crystal X-ray diffraction methods. The substance crystallizes in the triclinic space group P1̅ with one molecule per unit cell. The FTIR spectrum of the compound was also recorded and is briefly discussed. Some comparisons with other simple acesulfamate and saccharinate salts are also made.

The usefulness of post-genomics tools for characterization of the amine cross-talk in mammalian cells

2007 ◽  
Vol 35 (2) ◽  
pp. 381-385 ◽  
Author(s):  
F. Sánchez-Jiménez ◽  
R. Montañez ◽  
F. Correa-Fiz ◽  
P. Chaves ◽  
C. Rodríguez-Caso ◽  
...  
Keyword(s):  
Systems Biology ◽  
Mathematical Models ◽  
Mammalian Cells ◽  
State Of The Art ◽  
Molecular Approaches ◽  
Amine Metabolism ◽  
Genomics Tools ◽  
Stored Information

Evidence is growing in favour of a relationship between cancer and chronic inflammation, and particularly of the role of a polyamine and histamine metabolic interplay involved in these physiopathological problems, which are indeed highly complex biological systems. Decodification of the complex inter- and intra-cellular signalling mechanisms that control these effects is not an easy task, which must be helped by systems biology technologies, including new tools for location and integration of database-stored information and predictive mathematical models, as well as functional genomics and other experimental molecular approaches necessary for hypothesis validation. We review the state of the art and present our latest efforts in this area, focused on the amine metabolism field.

scholarly journals Effective intercalation of zein into Na-montmorillonite: role of the protein components and use of the developed biointerfaces

2016 ◽  
Vol 7 ◽  
pp. 1772-1782 ◽  
Author(s):  
Ana C S Alcântara ◽  
Margarita Darder ◽  
Pilar Aranda ◽  
Eduardo Ruiz-Hitzky
Keyword(s):  
Water Solution ◽  
Physicochemical Characterization ◽  
Layered Silicate ◽  
Aqueous Dispersion ◽  
Underlying Mechanism ◽  
Ethanol Medium ◽  
Major Storage Protein ◽  
Protein Components

Biohybrid materials based on the intercalation of zein, the major storage protein in corn, into sodium-exchanged montmorillonite were prepared following two synthesis strategies. The first one made use of zein dissolved in 80% (v/v) ethanol/water solution, the usual solvent for this protein, while the second method is new and uses a sequential process that implies the previous separation of zein components in absolute ethanol. This treatment of zein with ethanol renders a soluble yellow phase and an agglomerate of insoluble components, which are able to intercalate the layered silicate when an aqueous dispersion of montmorillonite is added to the ethanol medium containing both phases. The diverse steps in this second route were investigated individually in order to understand the underlying mechanism that drives to the intercalation of this complex hydrophobic biomacromolecule into the hydrophilic interlayer space of sodium-exchanged montmorillonite. In addition to physicochemical characterization of the resulting materials, these biohybrid interfaces were also evaluated as biofillers in the preparation of diverse ecofriendly nanocomposites.

scholarly journals Ru@hyperbranched Polymer for Hydrogenation of Levulinic Acid to Gamma-Valerolactone: The Role of the Catalyst Support

2022 ◽  
Vol 23 (2) ◽  
pp. 799
Author(s):  
Svetlana A. Sorokina ◽  
Stepan P. Mikhailov ◽  
Nina V. Kuchkina ◽  
Alexey V. Bykov ◽  
Alexander L. Vasiliev ◽  
...  
Keyword(s):  
Levulinic Acid ◽  
Catalyst Support ◽  
Physicochemical Characterization ◽  
Significant Loss ◽  
Catalyst Loading ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Low Catalyst Loading

Hydrogenation of levulinic acid (LA) obtained from cellulose biomass is a promising path for production of γ-valerolactone (GVL)—a component of biofuel. In this work, we developed Ru nanoparticle containing nanocomposites based on hyperbranched pyridylphenylene polymer, serving as multiligand and stabilizing matrix. The functionalization of the nanocomposite with sulfuric acid significantly enhances the activity of the catalyst in the selective hydrogenation of LA to GVL and allows the reaction to proceed under mild reaction conditions (100 °C, 2 MPa of H2) in water and low catalyst loading (0.016 mol.%) with a quantitative yield of GVL and selectivity up to 100%. The catalysts were successfully reused four times without a significant loss of activity. A comprehensive physicochemical characterization of the catalysts allowed us to assess structure-property relationships and to uncover an important role of the polymeric support in the efficient GVL synthesis.

scholarly journals Synthesis, crystal structure, and theoretical studies of a macrocyclic silver(I) complex of imino-pyridyl Schiff base ligand

2021 ◽  
Vol 12 (3) ◽  
pp. 248-255
Author(s):  
Jahangir Mondal ◽  
Meman Sahu ◽  
Bhaskar Sharma ◽  
Rakesh Ganguly ◽  
Shubhamoy Chowdhury ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Complex I ◽  
Average Distance ◽  
Spectroscopic Techniques ◽  
Triclinic Space Group ◽  
X Ray ◽  
Elemental Analyses ◽  
Photophysical Studies ◽  
Pyridyl Ligand

The synthesis and characterization of an imino-pyridyl ligand N,N'-(butane-1,4-diyl)bis(1-(pyridin-2-yl)methanimine) (L) and its Ag(I)ClO4 complex (I) by various spectroscopic techniques and elemental analyses is presented in this study. X-ray single crystal structure of complex I revealed that in complex I, each Ag(I) ion is tetra coordinated with two pyridine N-atoms and two imine N-atoms of the ligand L, forming a macrocyclic dimeric Ag(I) grid. In the macrocyclic dimer complex I, Ag-Ag separation along the chain is 5.318 Å. The Ag-Npy average distance is 2.396 Å and that of the Ag-Nim is 2.257 Å. The macrocyclic dimer complex I is supramolecularly arranged by π-stacking interactions. Computational, Hirshfeld surface analysis and photophysical studies on ligand L and complex I have also been performed. Crystal data for C32H36Ag2Cl2N8O8 (M =947.33 g/mol): Triclinic, space group P-1 (no. 2), a = 9.1714(12) Å, b = 10.4373(14) Å, c = 10.8297(14) Å, α = 112.317(3)°, β = 91.391(3)°, γ = 92.353(3)°, V = 957.3(2) Å3, Z = 1, T = 293.15 K, μ(MoKα) = 1.220 mm-1, Dcalc = 1.643 g/cm3, 10248 reflections measured (4.07° ≤ 2Θ ≤ 53.098°), 3966 unique (Rint = 0.0280, Rsigma = 0.0331) which were used in all calculations. The final R1 was 0.0722 (I > 2σ(I)) and wR2 was 0.2229 (all data).

Crystal Structure of Na9[H3W12O42]·24H2O, a Compound Containing the Protonated Paratungstate B Anion ('Acid Paratungstate'), and Cyclic Voltammetry of Acidified [H2W12O42]10- Solutions

1999 ◽  
Vol 52 (10) ◽  
pp. 955 ◽  
Author(s):  
Annette L. Nolan ◽  
Eric N. Wilkes ◽  
Trevor W. Hambley ◽  
Christine C. Allen ◽  
Robert C. Burns ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cyclic Voltammetry ◽  
Hydrogen Atom ◽  
Internal Cavity ◽  
Molecular Orbital Calculations ◽  
Hydrogen Atoms ◽  
Triclinic Space Group ◽  
Electrochemically Active ◽  
Paratungstate B

Crystallization of a solid at pH 4.0 from an aqueous acidified Rh3+–[WO4]2− solution resulted in the isolation of Na9[H3W12O42]·24H 2 O, which contains the protonated paratungstate B anion and which is likely the species identified previously as ‘acid paratungstate’. The compound is triclinic, space group P1– , a 10.603(2), b 12.134(3), c 14.042(3) Å, α 114.78(1), β 101.84(1), γ 108.34(1)˚, V 1432.9(5) Å3 , Z 1, and the structure was solved to an R1 value of 0.0404 (wR 2 0.1108) for 5997 independent observed reflections. The anion exhibits essentially the same isopolytungstate framework as paratungstate B, [H2W12O42]10− , consisting of two W3O13 and two W3O14 structural subunits linked by shared vertices. Bond valence arguments place two of the hydrogen atoms unequivocally in the internal cavity of the anion, with the remaining hydrogen atom also likely located in this cavity, but disordered over several internal oxygen atoms. The protonation of [H2W12O42 ]10− is shown to lead to species that are electrochemically reducible. Extended-HÜckel molecular orbital calculations confirm that protonation of paratungstate B within the internal cavity leads to a change in composition of the LUMO, now based mainly on electrochemically reducible W3O13 as opposed to (essentially) non-reducible W3O14 structural subunits. This results in species that are considerably more electrochemically active than the unprotonated anion. The role of [H3W12O42]9− as an intermediate in the polymerization of [WO4]2− to give the solution form of ψ-metatungstate, [H7W11O40]7− , which crystallizes as [H4W11O38]6− , is also discussed.

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