<p>This work describes the synthesis and initial characterization of the biological activity of a family of EAAT3 preferring inhibitors, L-β-benzyl aspartate (L-β-BA) and L-β-BA derivatives. L-β-BA and derivatives were initially synthesized in an approximate 2:1 ratio of diasteromers (threo:erythro), using base promoted enolate addition. Kinetic analysis of 3H-D-aspartate uptake into C17.2 cells expressing the hEAATs demonstrated that L-threo-β-BA is the more potent diastereomer (Ki values of 9 µM for EAAT1, 10.0 µM for EAAT2 and 0.8 µM for EAAT3), acts competitively, and exhibits a 10-fold preference for EAAT3 compared to EAAT1 and EAAT2. Electrophysiological recordings of EAAT-mediated currents in Xenopus oocytes further identified L-β-BA as a non-substrate inhibitor. Derivatives of L-β-BA were prepared and characterized for the ability to inhibit 3H-D-aspartate uptake into hEAAT1-3 expressing C17.2 cells. Computational modeling and analysis of structure activity data suggest the area the aromatic moiety of L-β-BA derivatives probe is 1) 3-dimentionally confined, 2) more tolerant of substitutions at the 3 and 5 positions than the 4 position, 3) at least partially distinct from the area probed by L-TBOA and 4) more accessible in the EAAT3 protein than EAAT1 and EAAT2. Computational modeling supports the pharmacological data and lends insight into the selectivity observed with L-β-BA derivatives. Docking studies suggest that H-bonding interactions of L-β-BA derivatives with key residues in the binding site position L-β-BA analogues in a unique manner that is better tolerated in the EAAT3 protein than in the EAAT1 and EAAT2 proteins.</p>
| Identifer | oai:union.ndltd.org:MONTANA/oai:etd.lib.umt.edu:etd-03212009-152926 |
| Date | 28 April 2009 |
| Creators | Mavencamp, Terri Lynn |
| Contributors | Christopher S Esslinger, Richard J Bridges, Diana I Lurie, Mark L Grimes, Michael P Kavanaugh |
| Publisher | The University of Montana |
| Source Sets | University of Montana Missoula |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.umt.edu/theses/available/etd-03212009-152926/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Montana or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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