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| Content Provider | World Health Organization (WHO)-Global Index Medicus |
|---|---|
| Author | Shishkanova, Tatiana V. Gale, Philip A. Sessler, Jonathan L. Král, Vladimír |
| Description | Author Affiliation: Sessler JL ( Department of Chemistry and Biochemistry and Institute for Cellular and Molecular Biology, University of Texas, Austin, TX 78712-1167, USA. sessler@mail.utexas.edu); |
| Abstract | The synthesis and characterization of two cytosine-substituted calix[4]pyrrole conjugates, bearing the appended cytosine attached at either a beta- or meso-pyrrolic position, is described. These systems were tested as nucleotide-selective carriers and as active components of nucleotide-sensing ion-selective electrodes at pH 6.6. Studies of carrier selectivity were made using a Pressman-type model membrane system consisting of an initial pH 6.0 aqueous phase, an intervening dichloromethane barrier containing the calix[4]pyrrole conjugate, and a receiving basic aqueous phase. Good selectivity for the Watson-Crick complementary nucleotide, 5'-guanosine monophosphate (5'-GMP), was seen in the case of the meso-linked conjugate with the relative rates of through-membrane transport being 7.7:4.1:1 for 5'-GMP, 5'-AMP, and 5'-CMP, respectively. By contrast, the beta-substituted conjugate, while showing a selectivity for 5'-GMP that was enhanced relative to unsubstituted calix[4]pyrrole, was found to transport 5'-CMP roughly 4.5 times more quickly than 5'-GMP. Higher selectivities were also found for 5'-CMP when both the beta- and meso-substituted conjugates were incorporated into polyvinyl chloride membranes and tested as ion selective electrodes at pH 6.6, whereas near-equal selectivities were observed for 5'-CMP and 5'-GMP in the case of unsubstituted calix[4]pyrroles. These seemingly disparate results are consistent with a picture wherein the meso-substituted cytosine calix[4]pyrrole conjugate, but not its beta-linked congener, is capable of acting as a ditopic receptor, binding concurrently both the phosphate anion and nucleobase portions of 5'-GMP to the calixpyrrole core and cytosine 'tails' of the molecule, respectively, with the effect of this binding being most apparent under the conditions of the transport experiments. |
| ISSN | 00278424 |
| e-ISSN | 10916490 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Issue Number | 8 |
| Volume Number | 99 |
| Language | English |
| Publisher | National Academy of Sciences |
| Publisher Date | 2002-04-01 |
| Publisher Place | United States |
| Access Restriction | Open |
| Subject Keyword | Cytosine Chemistry Guanosine Monophosphate Pyrroles Calixarenes Guanosine Metabolism Hydrogen-Ion Concentration Kinetics Macromolecular Substances Models, Chemical Phosphates Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Multidisciplinary |
| Content Type | Text |
| Resource Type | Article |
| Subject | Multidisciplinary |
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