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Wińska P, Sobiepanek A, Pawlak K, Staniszewska M, Cieśla J. Phosphorylation of Thymidylate Synthase and Dihydrofolate Reductase in Cancer Cells and the Effect of CK2α Silencing. Int J Mol Sci 2023; 24:ijms24033023. [PMID: 36769342 PMCID: PMC9917831 DOI: 10.3390/ijms24033023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/30/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023] Open
Abstract
Our previous research suggests an important regulatory role of CK2-mediated phosphorylation of enzymes involved in the thymidylate biosynthesis cycle, i.e., thymidylate synthase (TS), dihydrofolate reductase (DHFR), and serine hydroxymethyltransferase (SHMT). The aim of this study was to show whether silencing of the CK2α gene affects TS and DHFR expression in A-549 cells. Additionally, we attempted to identify the endogenous kinases that phosphorylate TS and DHFR in CCRF-CEM and A-549 cells. We used immunodetection, immunofluorescence/confocal analyses, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), in-gel kinase assay, and mass spectrometry analysis. Our results demonstrate that silencing of the CK2α gene in lung adenocarcinoma cells significantly increases both TS and DHFR expression and affects their cellular distribution. Additionally, we show for the first time that both TS and DHFR are very likely phosphorylated by endogenous CK2 in two types of cancer cells, i.e., acute lymphoblastic leukaemia and lung adenocarcinoma. Moreover, our studies indicate that DHFR is phosphorylated intracellularly by CK2 to a greater extent in leukaemia cells than in lung adenocarcinoma cells. Interestingly, in-gel kinase assay results indicate that the CK2α' isoform was more active than the CK2α subunit. Our results confirm the previous studies concerning the physiological relevance of CK2-mediated phosphorylation of TS and DHFR.
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Affiliation(s)
- Patrycja Wińska
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
- Correspondence: (P.W.); (M.S.); Tel.: +48-222-345-573 (P.W.); +48-606-438-241 (M.S.)
| | - Anna Sobiepanek
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
| | - Katarzyna Pawlak
- Chair of Analytical Chemistry, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
| | - Monika Staniszewska
- Centre for Advanced Materials and Technologies, Warsaw University of Technology, Poleczki 19, 02-822 Warsaw, Poland
- Correspondence: (P.W.); (M.S.); Tel.: +48-222-345-573 (P.W.); +48-606-438-241 (M.S.)
| | - Joanna Cieśla
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
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2
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Wińska P, Widło Ł, Senkara E, Koronkiewicz M, Cieśla JM, Krzyśko A, Skierka K, Cieśla J. Inhibition of Protein Kinase CK2 Affects Thymidylate Synthesis Cycle Enzyme Level and Distribution in Human Cancer Cells. Front Mol Biosci 2022; 9:847829. [PMID: 35281258 PMCID: PMC8914513 DOI: 10.3389/fmolb.2022.847829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Thymidylate synthase (TS), dihydrofolate reductase (DHFR), and serine hydroxymethyltransferase (SHMT) constitute the thymidylate synthesis cycle providing thymidylate for DNA synthesis and repair. Our previous studies indicated that TS and DHFR are the substrates of protein kinase CK2. This work has been aimed at the elucidation of the effect of CK2 activity on cell cycle progression, thymidylate synthesis enzyme expression and localization, and the role of CK2-mediated TS phosphorylation in in vitro di- and trimolecular complex formation. The results were obtained by means of western blot, confocal microscopy, flow cytometry, quantitative polymerase chain reaction (QPCR), quartz crystal microbalance with dissipation monitoring (QCM-D), and microthermophoresis (MST). Our research indicates that CK2 inhibition does not change the levels of the transcripts; however, it affects the protein levels of DHFR and TS in both tested cell lines, i.e., A549 and CCRF-CEM, and the level of SHMT1 in CCRF-CEM cells. Moreover, we show that CK2-mediated phosphorylation of TS enables the protein (pTS) interaction with SHMT1 and leads to the stability of the tri-complex containing SHMT1, DHFR, and pTS. Our results suggest an important regulatory role of CK2-mediated phosphorylation for inter- and intracellular protein level of enzymes involved in the thymidylate biosynthesis cycle.
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Affiliation(s)
- Patrycja Wińska
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
- *Correspondence: Patrycja Wińska, ; Joanna Cieśla,
| | - Łukasz Widło
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Elżbieta Senkara
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | | | - Jarosław M. Cieśla
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Alicja Krzyśko
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Katarzyna Skierka
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
| | - Joanna Cieśla
- Chair of Drug and Cosmetics Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland
- *Correspondence: Patrycja Wińska, ; Joanna Cieśla,
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3
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Zhao LN, Björklund M, Caldez MJ, Zheng J, Kaldis P. Therapeutic targeting of the mitochondrial one-carbon pathway: perspectives, pitfalls, and potential. Oncogene 2021; 40:2339-2354. [PMID: 33664451 DOI: 10.1038/s41388-021-01695-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/27/2021] [Accepted: 02/02/2021] [Indexed: 02/07/2023]
Abstract
Most of the drugs currently prescribed for cancer treatment are riddled with substantial side effects. In order to develop more effective and specific strategies to treat cancer, it is of importance to understand the biology of drug targets, particularly the newly emerging ones. A comprehensive evaluation of these targets will benefit drug development with increased likelihood for success in clinical trials. The folate-mediated one-carbon (1C) metabolism pathway has drawn renewed attention as it is often hyperactivated in cancer and inhibition of this pathway displays promise in developing anticancer treatment with fewer side effects. Here, we systematically review individual enzymes in the 1C pathway and their compartmentalization to mitochondria and cytosol. Based on these insight, we conclude that (1) except the known 1C targets (DHFR, GART, and TYMS), MTHFD2 emerges as good drug target, especially for treating hematopoietic cancers such as CLL, AML, and T-cell lymphoma; (2) SHMT2 and MTHFD1L are potential drug targets; and (3) MTHFD2L and ALDH1L2 should not be considered as drug targets. We highlight MTHFD2 as an excellent therapeutic target and SHMT2 as a complementary target based on structural/biochemical considerations and up-to-date inhibitor development, which underscores the perspectives of their therapeutic potential.
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Affiliation(s)
- Li Na Zhao
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
| | - Mikael Björklund
- Zhejiang University-University of Edinburgh (ZJU-UoE) Institute, Haining, Zhejiang, PR China.,2nd Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, PR China.,Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK
| | - Matias J Caldez
- Laboratory of Host Defense, The World Premier International Research Center Initiative (WPI) Immunology Frontier Research Center (IFReC), Osaka University, Osaka, Japan
| | - Jie Zheng
- School of Information Science and Technology, Shanghai Tech University, Shanghai, PR China
| | - Philipp Kaldis
- Department of Clinical Sciences, Lund University, Malmö, Sweden.
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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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Ferrari S, Severi L, Pozzi C, Quotadamo A, Ponterini G, Losi L, Marverti G, Costi MP. Human Thymidylate Synthase Inhibitors Halting Ovarian Cancer Growth. VITAMINS AND HORMONES 2018; 107:473-513. [PMID: 29544641 DOI: 10.1016/bs.vh.2017.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Human thymidylate synthase (hTS) has an important role in DNA biosynthesis, thus it is essential for cell survival. TS is involved in the folate pathways, specifically in the de novo pyrimidine biosynthesis. Structure and functions are intimately correlated, account for cellular activity and, in a broader view, with in vivo mechanisms. hTS is a target for anticancer agents, some of which are clinical drugs. The understanding of the detailed mechanism of TS inhibition by currently used drugs and of the interaction with the mechanism of action of other anticancer agents can suggest new perspective of TS inhibition able to improve the anticancer effect and to overcome drug resistance. TS-targeting drugs in therapy today are inhibitors that bind at the active site and that mostly resemble the substrates. Nonsubstrate analogs offer an opportunity for allosteric binding and novel mode of inhibition in the cancer cells. This chapter illustrates the relationship among the large number of hTS actions at molecular and clinical levels, its role as a target for ovarian cancer therapy, in particular in cases of overexpression of hTS and other folate proteins such as those induced by platinum drug treatments, and address the potential combination of TS inhibitors with other suitable anticancer agents.
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Affiliation(s)
| | - Leda Severi
- University of Modena and Reggio Emilia, Modena, Italy
| | | | | | | | - Lorena Losi
- University of Modena and Reggio Emilia, Modena, Italy
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Jarmuła A, Wilk P, Maj P, Ludwiczak J, Dowierciał A, Banaszak K, Rypniewski W, Cieśla J, Dąbrowska M, Frączyk T, Bronowska AK, Jakowiecki J, Filipek S, Rode W. Crystal structures of nematode (parasitic T. spiralis and free living C. elegans), compared to mammalian, thymidylate synthases (TS). Molecular docking and molecular dynamics simulations in search for nematode-specific inhibitors of TS. J Mol Graph Model 2017; 77:33-50. [PMID: 28826032 DOI: 10.1016/j.jmgm.2017.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/05/2017] [Accepted: 08/07/2017] [Indexed: 01/01/2023]
Abstract
Three crystal structures are presented of nematode thymidylate synthases (TS), including Caenorhabditis elegans (Ce) enzyme without ligands and its ternary complex with dUMP and Raltitrexed, and binary complex of Trichinella spiralis (Ts) enzyme with dUMP. In search of differences potentially relevant for the development of species-specific inhibitors of the nematode enzyme, a comparison was made of the present Ce and Ts enzyme structures, as well as binary complex of Ce enzyme with dUMP, with the corresponding mammalian (human, mouse and rat) enzyme crystal structures. To complement the comparison, tCONCOORD computations were performed to evaluate dynamic behaviors of mammalian and nematode TS structures. Finally, comparative molecular docking combined with molecular dynamics and free energy of binding calculations were carried out to search for ligands showing selective affinity to T. spiralis TS. Despite an overall strong similarity in structure and dynamics of nematode vs mammalian TSs, a pool of ligands demonstrating predictively a strong and selective binding to TsTS has been delimited. These compounds, the E63 family, locate in the dimerization interface of TsTS where they exert species-specific interactions with certain non-conserved residues, including hydrogen bonds with Thr174 and hydrophobic contacts with Phe192, Cys191 and Tyr152. The E63 family of ligands opens the possibility of future development of selective inhibitors of TsTS and effective agents against trichinellosis.
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Affiliation(s)
- Adam Jarmuła
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland.
| | - Piotr Wilk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland; Macromolecular Crystallography (BESSY-MX), Berlin, Germany
| | - Piotr Maj
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | - Jan Ludwiczak
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland; Centre of New Technologies, University of Warsaw, Warszawa, Poland
| | - Anna Dowierciał
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | - Katarzyna Banaszak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Wojciech Rypniewski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Joanna Cieśla
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | - Magdalena Dąbrowska
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | - Tomasz Frączyk
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
| | | | | | | | - Wojciech Rode
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warszawa, Poland
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Chen D, Jansson A, Sim D, Larsson A, Nordlund P. Structural analyses of human thymidylate synthase reveal a site that may control conformational switching between active and inactive states. J Biol Chem 2017; 292:13449-13458. [PMID: 28634233 PMCID: PMC5555203 DOI: 10.1074/jbc.m117.787267] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 06/18/2017] [Indexed: 12/16/2022] Open
Abstract
Thymidylate synthase (TS) is the sole enzyme responsible for de novo biosynthesis of thymidylate (TMP) and is essential for cell proliferation and survival. Inhibition of human TS (hTS) has been extensively investigated for cancer chemotherapy, but several aspects of its activity and regulation are still uncertain. In this study, we performed comprehensive structural and biophysical studies of hTS using crystallography and thermal shift assay and provided the first detailed structural information on the conformational changes induced by ligand binding to the hTS active site. We found that upon binding of the antifolate agents raltitrexed and nolatrexed, the two insert regions in hTS, the functions of which are unclear, undergo positional shifts toward the catalytic center. We investigated the inactive conformation of hTS and found that the two insert regions are also involved in the conformational transition between the active and inactive state of hTS. Moreover, we identified a ligand-binding site in the dimer interface, suggesting that the cavity in the dimer interface could serve as an allosteric site of hTS to regulate the conformational switching between the active and inactive states. On the basis of these findings, we propose a regulatory mechanism of hTS activity that involves allosteric regulation of interactions of hTS with its own mRNA depending on cellular demands for TMP.
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Affiliation(s)
- Dan Chen
- From the School of Biological Sciences, Lab 07-02 and
| | - Anna Jansson
- From the School of Biological Sciences, Lab 07-02 and
| | - Daniel Sim
- Lab 07-01, Nanyang Technological University, 61 Biopolis Drive (Proteos), Singapore 138673
| | | | - Pär Nordlund
- From the School of Biological Sciences, Lab 07-02 and
- the Institute of Cellular and Molecular Biology, A*STAR, 61 Biopolis Drive (Proteos), Singapore 138673, and
- the Department of Medical Biochemistry & Biophysics, Division of Biophysics, Karolinska Institutet, Scheeles väg 2, Stockholm 17177, Sweden
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8
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Deschamps P, Réty S, Bareille J, Leulliot N. Crystal structure of the active form of native human thymidylate synthase in the absence of bound substrates. Acta Crystallogr F Struct Biol Commun 2017; 73:336-341. [PMID: 28580921 PMCID: PMC5458390 DOI: 10.1107/s2053230x17007233] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 05/16/2017] [Indexed: 11/10/2022] Open
Abstract
Human thymidylate synthase (hTS) provides the sole de novo intracellular source of thymidine 5'-monophosphate (dTMP). hTS is required for DNA replication prior to cell division, making it an attractive target for anticancer chemotherapy and drug discovery. hTS binds 2'-deoxyuridine 5'-monophosphate (dUMP) and the folate co-substrate N5,N10-methylenetetrahydrofolate (meTHF) in a pocket near the catalytic residue Cys195. The catalytic loop, which is composed of amino-acid residues 181-197, can adopt two distinct conformations related by a 180° rotation. In the active conformation Cys195 is close to the active site, while in the inactive conformation it is rotated and Cys195 is too distant from the active site for catalysis. Several hTS structures, either native or engineered, have been solved in the active conformation in complex with ligands or inhibitors and at different salt concentrations. However, apo hTS structures have been solved in an inactive conformation in high-salt and low-salt conditions (PDB entries 1ypv, 4h1i, 4gyh, 3egy and 3ehi). Here, the structure of apo hTS crystallized in the active form with sulfate ions coordinated by the arginine residue that binds dUMP is reported.
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Affiliation(s)
- P. Deschamps
- Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris, France
| | - S. Réty
- Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris, France
| | - J. Bareille
- Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris, France
| | - N. Leulliot
- Laboratoire de Cristallographie et RMN Biologiques, UMR CNRS 8015, Université Paris Descartes, Sorbonne Paris Cité, Faculté de Pharmacie de Paris, Paris, France
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9
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Cole CA, Mukhopadhyay R, Omar H, Hennig M, Valafar H. Structure Calculation and Reconstruction of Discrete-State Dynamics from Residual Dipolar Couplings. J Chem Theory Comput 2016; 12:1408-22. [PMID: 26984680 DOI: 10.1021/acs.jctc.5b01091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Residual dipolar couplings (RDCs) acquired by nuclear magnetic resonance (NMR) spectroscopy are an indispensable source of information in investigation of molecular structures and dynamics. Here, we present a comprehensive strategy for structure calculation and reconstruction of discrete-state dynamics from RDC data that is based on the singular value decomposition (SVD) method of order tensor estimation. In addition to structure determination, we provide a mechanism of producing an ensemble of conformations for the dynamical regions of a protein from RDC data. The developed methodology has been tested on simulated RDC data with ±1 Hz of error from an 83 residue α protein (PDB ID 1A1Z ) and a 213 residue α/β protein DGCR8 (PDB ID 2YT4 ). In nearly all instances, our method reproduced the structure of the protein including the conformational ensemble to within less than 2 Å. On the basis of our investigations, arc motions with more than 30° of rotation are identified as internal dynamics and are reconstructed with sufficient accuracy. Furthermore, states with relative occupancies above 20% are consistently recognized and reconstructed successfully. Arc motions with a magnitude of 15° or relative occupancy of less than 10% are consistently unrecognizable as dynamical regions within the context of ±1 Hz of error.
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Affiliation(s)
- Casey A Cole
- Department of Computer Science & Engineering, University of South Carolina , Columbia, South Carolina 29208, United States
| | - Rishi Mukhopadhyay
- Department of Computer Science & Engineering, University of South Carolina , Columbia, South Carolina 29208, United States
| | - Hanin Omar
- Department of Computer Science & Engineering, University of South Carolina , Columbia, South Carolina 29208, United States
| | - Mirko Hennig
- Nutrition Research Institute, University of North Carolina at Chapel Hill , Kannapolis, North Carolina 27514, United States
| | - Homayoun Valafar
- Department of Computer Science & Engineering, University of South Carolina , Columbia, South Carolina 29208, United States
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10
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Salo-Ahen OMH, Tochowicz A, Pozzi C, Cardinale D, Ferrari S, Boum Y, Mangani S, Stroud RM, Saxena P, Myllykallio H, Costi MP, Ponterini G, Wade RC. Hotspots in an obligate homodimeric anticancer target. Structural and functional effects of interfacial mutations in human thymidylate synthase. J Med Chem 2015; 58:3572-81. [PMID: 25798950 DOI: 10.1021/acs.jmedchem.5b00137] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Human thymidylate synthase (hTS), a target for antiproliferative drugs, is an obligate homodimer. Single-point mutations to alanine at the monomer-monomer interface may enable the identification of specific residues that delineate sites for drugs aimed at perturbing the protein-protein interactions critical for activity. We computationally identified putative hotspot residues at the interface and designed mutants to perturb the intersubunit interaction. Dimer dissociation constants measured by a FRET-based assay range from 60 nM for wild-type hTS up to about 1 mM for single-point mutants and agree with computational predictions of the effects of these mutations. Mutations that are remote from the active site retain full or partial activity, although the substrate KM values were generally higher and the dimer was less stable. The lower dimer stability of the mutants can facilitate access to the dimer interface by small molecules and thereby aid the design of inhibitors that bind at the dimer interface.
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Affiliation(s)
- Outi M H Salo-Ahen
- †Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies, 69118 Heidelberg, Germany
| | - Anna Tochowicz
- ‡Department of Biochemistry and Biophysics, University of California-San Francisco, San Francisco, California 94158, United States
| | - Cecilia Pozzi
- §Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy
| | - Daniela Cardinale
- ∥Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Stefania Ferrari
- ∥Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Yap Boum
- ⊥Ecole Polytechnique, CNRS UMR7645, INSERM U696, 91128 Palaiseau, France
| | - Stefano Mangani
- §Department of Biotechnology, Chemistry and Pharmacy, University of Siena, 53100 Siena, Italy
| | - Robert M Stroud
- ‡Department of Biochemistry and Biophysics, University of California-San Francisco, San Francisco, California 94158, United States
| | - Puneet Saxena
- ∥Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Hannu Myllykallio
- ⊥Ecole Polytechnique, CNRS UMR7645, INSERM U696, 91128 Palaiseau, France
| | - Maria Paola Costi
- ∥Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Glauco Ponterini
- ∥Department of Life Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Rebecca C Wade
- †Molecular and Cellular Modeling Group, Heidelberg Institute for Theoretical Studies, 69118 Heidelberg, Germany.,#Center for Molecular Biology, DKFZ-ZMBH Alliance, and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, 69120 Heidelberg, Germany
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11
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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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Luo B, Repalli J, Yousef AM, Johnson SR, Lebioda L, Berger SH. Human thymidylate synthase with loop 181-197 stabilized in an inactive conformation: ligand interactions, phosphorylation, and inhibition profiles. Protein Sci 2011; 20:87-94. [PMID: 21064161 DOI: 10.1002/pro.539] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Thymidylate synthase (TS) is a well-validated cancer target that undergoes conformational switching between active and inactive states. Two mutant human TS (hTS) proteins are predicted from crystal structures to be stabilized in an inactive conformation to differing extents, with M190K populating the inactive conformation to a greater extent than A191K. Studies of intrinsic fluorescence and circular dichroism revealed that the structures of the mutants differ from those of hTS. Inclusion of the substrate dUMP was without effect on M190K but induced structural changes in A191K that are unique, relative to hTS. The effect of strong stabilization in an inactive conformation on protein phosphorylation by casein kinase 2 (CK2) was investigated. M190K was highly phosphorylated by CK2 relative to an active-stabilized mutant, R163K hTS. dUMP had no detectable effect on phosphorylation of M190K; however, dUMP inhibited phosphorylation of hTS and R163K. Studies of temperature dependence of catalysis revealed that the E(act) and temperature optimum are higher for A191K than hTS. The potency of the active-site inhibitor, raltitrexed, was lower for A191K than hTS. The response of A191K to the allosteric inhibitor, propylene diphosphonate (PDPA) was concentration dependent. Mixed inhibition was observed at low concentrations; at higher concentrations, A191K exhibited nonhyperbolic behavior with respect to dUMP and inhibition of catalysis was reversed by substrate saturation. In summary, inactive-stabilized mutants differ from hTS in thermal stability and response to substrates and PDPA. Importantly, phosphorylation of hTS by CK2 is selective for the inactive conformation, providing the first indication of physiological relevance for conformational switching.
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Affiliation(s)
- BeiBei Luo
- Department of Pharmaceutical Sciences, University of South Carolina, Columbia, South Carolina 29208, USA
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Garg D, Henrich S, Salo-Ahen OMH, Myllykallio H, Costi MP, Wade RC. Novel approaches for targeting thymidylate synthase to overcome the resistance and toxicity of anticancer drugs. J Med Chem 2010; 53:6539-49. [PMID: 20527892 DOI: 10.1021/jm901869w] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Divita Garg
- Molecular and Cellular Modeling Group, Heidelberg Institute of Theoretical Studies gGmbH, Heidelberg, Germany
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Huang X, Gibson LM, Bell BJ, Lovelace LL, Peña MMO, Berger FG, Berger SH, Lebioda L. Replacement of Val3 in human thymidylate synthase affects its kinetic properties and intracellular stability . Biochemistry 2010; 49:2475-82. [PMID: 20151707 DOI: 10.1021/bi901457e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Human and other mammalian thymidylate synthase (TS) enzymes have an N-terminal extension of approximately 27 amino acids that is not present in bacterial TSs. The extension, which is disordered in all reported crystal structures of TSs, has been considered to play a primary role in protein turnover but not in catalytic activity. In mammalian cells, the variant V3A has a half-life similar to that of wild-type human TS (wt hTS) while V3T is much more stable; V3L, V3F, and V3Y have half-lives approximately half of that for wt hTS. Catalytic turnover rates for most Val3 mutants are only slightly diminished, as expected. However, two mutants, V3L and V3F, have strongly compromised dUMP binding, with K(m,app) values increased by factors of 47 and 58, respectively. For V3L, this observation can be explained by stabilization of the inactive conformation of the loop of residues 181-197, which prevents substrate binding. In the crystal structure of V3L, electron density corresponding to a leucine residue is present in a position that stabilizes the loop of residues 181-197 in the inactive conformation. Since this density is not observed in other mutants and all other leucine residues are ordered in this structure, it is likely that this density represents Leu3. In the crystal structure of a V3F.FdUMP binary complex, the nucleotide is bound in an alternative mode to that proposed for the catalytic complex, indicating that the high K(m,app) value is caused not by stabilization of the inactive conformer but by substrate binding in a nonproductive, inhibitory site. These observations show that the N-terminal extension affects the conformational state of the hTS catalytic region. Each of the mechanisms leading to the high K(m,app) values can be exploited to facilitate design of compounds acting as allosteric inhibitors of hTS.
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Affiliation(s)
- Xiao Huang
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, USA
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