Dataset Information

Molecular modeling study of chiral separation and recognition mechanism of ?-adrenergic antagonists by capillary electrophoresis.

ABSTRACT: Chiral separations of five ?-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-?-cyclodextrin (CM-?-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-?-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five ?-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-?-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-?-CD, host-guest binding procedures of CM-?-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-?-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-?-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the -OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.

SUBMITTER: Li W

PROVIDER: S-EPMC3269715 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature

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Molecular modeling study of chiral separation and recognition mechanism of β-adrenergic antagonists by capillary electrophoresis.

Li Wuhong W Liu Changhai C Tan Guangguo G Zhang Xinrong X Zhu Zhenyu Z Chai Yifeng Y

International journal of molecular sciences 20120111 1

Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol) were studied by capillary electrophoresis using six cyclodextrins (CDs) as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD) exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β ...[more]

PMID: 22312281

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Project description:Phosphoinositides (PIs) and sphingolipids regulate many aspects of cell behavior and are often involved in disease processes such as oncogenesis. Capillary electrophoresis with laser induced fluorescence detection (CE-LIF) is emerging as an important tool for enzymatic assays of the metabolism of these lipids, particularly in cell-based formats. Previous separations of phosphoinositide lipids by CE required a complex buffer with polymer additives which had the disadvantages of high cost and/or short shelf life. Further a simultaneous separation of these classes of lipids has not been demonstrated in a robust buffer system. In the current work, a simple separation buffer based on NaH(2)PO(4) and 1-propanol was optimized to separate two sphingolipids and multiple phosphoinositides by CE. The NaH(2)PO(4) concentration, pH, 1-propanol fraction, and a surfactant additive to the buffer were individually optimized to achieve simultaneous separation of the sphingolipids and phosphoinositides. Fluorescein-labeled sphingosine (SFL) and sphingosine 1-phosphate (S1PFL), fluorescein-labeled phosphatidyl-inositol 4,5-bisphosphate (PIP2) and phosphatidyl-inositol 3,4,5-trisphosphate (PIP3), and bodipy-fluorescein (BFL)-labeled PIP2 and PIP3 were separated pairwise and in combination to demonstrate the generalizability of the method. Theoretical plate numbers achieved were as high as 2×10(5) in separating fluorophore-labeled PIP2 and PIP3. Detection limits for the 6 analytes were in the range of 10(-18)-10(-20)mol. The method also showed high reproducibility, as the relative standard deviation of the normalized migration time for each analyte in the simultaneous separation of all 6 compounds was less than 1%. The separation of a mixture composed of diacylglycerol (DAG) and multiple phosphoinositides was also demonstrated. As a final test, fluorescent lipid metabolites formed within cells loaded with BFLPIP2 were separated from a cell lysate as well as a single cell. This simple and robust separation method for SFL and S1PFL and various metabolites of phosphoinositide-related signal transduction is expected to enable improved enzymatic assays for biological and clinical applications.

Dataset Information

Molecular modeling study of chiral separation and recognition mechanism of ?-adrenergic antagonists by capillary electrophoresis.

Publications

Molecular modeling study of chiral separation and recognition mechanism of β-adrenergic antagonists by capillary electrophoresis.

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