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El-Mesallamy HO, El Magdoub HM, Chapman JM, Hamdy NM, Schaalan MF, Hammad LN, Berger SH. Biomolecular study of human thymidylate synthase conformer-selective inhibitors: New chemotherapeutic approach. PLoS One 2018. [PMID: 29538414 PMCID: PMC5851609 DOI: 10.1371/journal.pone.0193810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Thymidylate synthase (TS) is a well-validated target for the therapy of adult cancers. Propane-1,3-diphosphonic acid (PDPA) has significant inhibitory properties against human thymidylate synthase (hTS) relative to mouse TS which is not predicted to adopt an inactive conformer. The current research aims to identify novel, lead inhibitors of hTS and examine the prediction that they bind selectively to hTS enzymes existing in different conformational equilibria. Conformer-selectivity was evaluated through performing activity inhibition studies, as well as intrinsic fluorescence (IF) studies in comparison to the known orthosteric inhibitor raltitrexed (RTX). Human TS was isolated from recombinant bacteria expressing either native hTS, capable of conformational switching, or an actively stabilized mutant (R163K-hTS). The examined test compounds were rationally or virtually predicted to have inhibitory activity against hTS. Among these compounds, glutarate, N-(4-carboxyphenyl) succinamic acid, and diglycolic anhydride showed higher selectivity towards native hTS as compared to R163K-hTS. The active site inhibitor RTX showed significantly higher inhibition of R163K-hTS relative to hTS. Targeting hTS via conformational selectivity represents a future approach for overcoming reported resistance towards active-state TS analogs.
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Affiliation(s)
- Hala O. El-Mesallamy
- Department of Biochemistry, Faculty of Pharmacy, Ain Sham University, Cairo, Egypt
- * E-mail:
| | - Hekmat M. El Magdoub
- Department of Biochemistry, Faculty of Pharmacy, Misr International University, Cairo, Egypt
| | - James M. Chapman
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, United States of America
| | - Nadia M. Hamdy
- Department of Biochemistry, Faculty of Pharmacy, Ain Sham University, Cairo, Egypt
| | - Mona F. Schaalan
- Department of Biochemistry, Faculty of Pharmacy, Misr International University, Cairo, Egypt
| | - Lamiaa N. Hammad
- Department of Biochemistry, Faculty of Pharmacy, Misr International University, Cairo, Egypt
| | - Sondra H. Berger
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of South Carolina, Columbia, SC, United States of America
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Dowierciał A, Jarmuła A, Wilk P, Rypniewski W, Kowalska M, Frączyk T, Cieśla J, Rode W. Mouse thymidylate synthase does not show the inactive conformation, observed for the human enzyme. Struct Chem 2016. [DOI: 10.1007/s11224-016-0840-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Sharma H, Landau MJ, Sullivan TJ, Kumar VP, Dahlgren MK, Jorgensen WL, Anderson KS. Virtual screening reveals allosteric inhibitors of the Toxoplasma gondii thymidylate synthase-dihydrofolate reductase. Bioorg Med Chem Lett 2013; 24:1232-5. [PMID: 24440298 DOI: 10.1016/j.bmcl.2013.12.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 11/28/2022]
Abstract
The parasite Toxoplasma gondii can lead to toxoplasmosis in those who are immunocompromised. To combat the infection, the enzyme responsible for nucleotide synthesis thymidylate synthase-dihydrofolate reductase (TS-DHFR) is a suitable drug target. We have used virtual screening to determine novel allosteric inhibitors at the interface between the two TS domains. Selected compounds from virtual screening inhibited TS activity. Thus, these results show that allosteric inhibition by small drug-like molecules can occur in T. gondii TS-DHFR and pave the way for new and potent species-specific inhibitors.
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Affiliation(s)
- Hitesh Sharma
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Mark J Landau
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Todd J Sullivan
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
| | - Vidya P Kumar
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
| | - Markus K Dahlgren
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
| | - William L Jorgensen
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, CT 06520, USA
| | - Karen S Anderson
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA; Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
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Landau MJ, Sharma H, Anderson KS. Selective peptide inhibitors of bifunctional thymidylate synthase-dihydrofolate reductase from Toxoplasma gondii provide insights into domain-domain communication and allosteric regulation. Protein Sci 2013; 22:1161-73. [PMID: 23813474 DOI: 10.1002/pro.2300] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 06/14/2013] [Accepted: 06/17/2013] [Indexed: 11/05/2022]
Abstract
The bifunctional enzyme thymidylate synthase-dihydrofolate reductase (TS-DHFR) plays an essential role in DNA synthesis and is unique to several species of pathogenic protozoans, including the parasite Toxoplasma gondii. Infection by T. gondii causes the prevalent disease toxoplasmosis, for which TS-DHFR is a major therapeutic target. Here, we design peptides that target the dimer interface between the TS domains of bifunctional T. gondii TS-DHFR by mimicking β-strands at the interface, revealing a previously unknown allosteric target. The current study shows that these β-strand mimetic peptides bind to the apo-enzyme in a species-selective manner to inhibit both the TS and distal DHFR. Fluorescence spectroscopy was used to monitor conformational switching of the TS domain and demonstrate that these peptides induce a conformational change in the enzyme. Using structure-guided mutagenesis, nonconserved residues in the linker between TS and DHFR were identified that play a key role in domain-domain communication and in peptide inhibition of the DHFR domain. These studies validate allosteric inhibition of apo-TS, specifically at the TS-TS interface, as a potential target for novel, species-specific therapeutics for treating T. gondii parasitic infections and overcoming drug resistance.
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Affiliation(s)
- Mark J Landau
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06510; Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, Connecticut, 06510
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