Parallel reaction pathways and noncovalent intermediates in thymidylate synthase revealed by experimental and computational tools.
| Autor: | Kholodar SA; Department of Chemistry, The University of Iowa, Iowa City, IA 52242-1727; svetlana.kholodar@gmail.com moliner@uji.es., Ghosh AK; Department of Chemistry, The University of Iowa, Iowa City, IA 52242-1727., Świderek K; Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castello, Spain., Moliner V; Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castello, Spain svetlana.kholodar@gmail.com moliner@uji.es., Kohen A; Department of Chemistry, The University of Iowa, Iowa City, IA 52242-1727. |
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| Jazyk: | angličtina |
| Zdroj: | Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2018 Oct 09; Vol. 115 (41), pp. 10311-10314. Date of Electronic Publication: 2018 Sep 24. |
| DOI: | 10.1073/pnas.1811059115 |
| Abstrakt: | Thymidylate synthase was one of the most studied enzymes due to its critical role in molecular pathogenesis of cancer. Nevertheless, many atomistic details of its chemical mechanism remain unknown or debated, thereby imposing limits on design of novel mechanism-based anticancer therapeutics. Here, we report unprecedented isolation and characterization of a previously proposed intact noncovalent bisubstrate intermediate formed in the reaction catalyzed by thymidylate synthase. Free-energy surfaces of the bisubstrate intermediates interconversions computed with quantum mechanics/molecular mechanics (QM/MM) methods and experimental assessment of the corresponding kinetics indicate that the species is the most abundant productive intermediate along the reaction coordinate, whereas accumulation of the covalent bisubstrate species largely occurs in a parallel nonproductive pathway. Our findings not only substantiate relevance of the previously proposed noncovalent intermediate but also support potential implications of the overstabilized covalent intermediate in drug design targeting DNA biosynthesis. Competing Interests: The authors declare no conflict of interest. (Copyright © 2018 the Author(s). Published by PNAS.) |
| Databáze: | MEDLINE |
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