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Morales-Polanco F, Bates C, Lui J, Casson J, Solari CA, Pizzinga M, Forte G, Griffin C, Garner KEL, Burt HE, Dixon HL, Hubbard S, Portela P, Ashe MP. Core Fermentation (CoFe) granules focus coordinated glycolytic mRNA localization and translation to fuel glucose fermentation. iScience 2021; 24:102069. [PMID: 33554071 PMCID: PMC7859310 DOI: 10.1016/j.isci.2021.102069] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/16/2020] [Accepted: 01/12/2021] [Indexed: 12/24/2022] Open
Abstract
Glycolysis is a fundamental metabolic pathway for glucose catabolism across biology, and glycolytic enzymes are among the most abundant proteins in cells. Their expression at such levels provides a particular challenge. Here we demonstrate that the glycolytic mRNAs are localized to granules in yeast and human cells. Detailed live cell and smFISH studies in yeast show that the mRNAs are actively translated in granules, and this translation appears critical for the localization. Furthermore, this arrangement is likely to facilitate the higher level organization and control of the glycolytic pathway. Indeed, the degree of fermentation required by cells is intrinsically connected to the extent of mRNA localization to granules. On this basis, we term these granules, core fermentation (CoFe) granules; they appear to represent translation factories, allowing high-level coordinated enzyme synthesis for a critical metabolic pathway.
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Affiliation(s)
- Fabian Morales-Polanco
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Christian Bates
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Jennifer Lui
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Joseph Casson
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Clara A Solari
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mariavittoria Pizzinga
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Gabriela Forte
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Claire Griffin
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Kirsten E L Garner
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Harriet E Burt
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Hannah L Dixon
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Simon Hubbard
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
| | - Paula Portela
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IQUIBICEN-CONICET, Buenos Aires, Argentina
| | - Mark P Ashe
- School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Michael Smith Building, Oxford Road, Manchester M13 9PT, UK
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Spurbeck RR, Harris PT, Raghunathan K, Arvidson DN, Arvidson CG. A Moonlighting Enolase from Lactobacillus gasseri does not Require Enzymatic Activity to Inhibit Neisseria gonorrhoeae Adherence to Epithelial Cells. Probiotics Antimicrob Proteins 2016; 7:193-202. [PMID: 25917402 DOI: 10.1007/s12602-015-9192-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Enolases are generally thought of as cytoplasmic enzymes involved in glycolysis and gluconeogenesis. However, several bacteria have active forms of enolase associated with the cell surface and these proteins are utilized for functions other than central metabolism. Recently, a surface-associated protein produced by Lactobacillus gasseri ATCC 33323 with homology to enolase was found to inhibit the adherence of the sexually transmitted pathogen, Neisseria gonorrhoeae, to epithelial cells in culture. Here, we show that the protein is an active enolase in vitro. A recombinantly expressed, C-terminal His-tagged version of the protein, His6-Eno3, inhibited gonococcal adherence. Assays utilizing inhibitors of enolase enzymatic activity showed that this inhibitory activity required the substrate-binding site to be in an open conformation; however, the enolase enzymatic activity of the protein was not necessary for inhibition of gonococcal adherence. An L. gasseri strain carrying an insertional mutation in eno3 was viable, indicating that eno3 is not an essential gene in L. gasseri 33323. This observation, along with the results of the enzyme assays, is consistent with reports that this strain encodes more than one enolase. Here we show that the three L. gasseri genes annotated as encoding an enolase are expressed. The L. gasseri eno3 mutant exhibited reduced, but not abolished, inhibition of gonococcal adherence, which supports the hypothesis that L. gasseri inhibition of gonococcal adherence is a multifactorial process.
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Affiliation(s)
- Rachel R Spurbeck
- The Genetics Program, Michigan State University, East Lansing, MI, USA
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3
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Zadvornyy OA, Boyd ES, Posewitz MC, Zorin NA, Peters JW. Biochemical and Structural Characterization of Enolase from Chloroflexus aurantiacus: Evidence for a Thermophilic Origin. Front Bioeng Biotechnol 2015; 3:74. [PMID: 26082925 PMCID: PMC4450660 DOI: 10.3389/fbioe.2015.00074] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/08/2015] [Indexed: 11/13/2022] Open
Abstract
Enolase catalyzes the conversion of 2-phosphoglycerate to phosphoenolpyruvate during both glycolysis and gluconeogenesis, and is required by all three domains of life. Here, we report the purification and biochemical and structural characterization of enolase from Chloroflexus aurantiacus, a thermophilic anoxygenic phototroph affiliated with the green non-sulfur bacteria. The protein was purified as a homodimer with a subunit molecular weight of 46 kDa. The temperature optimum for enolase catalysis was 80°C, close to the measured thermal stability of the protein which was determined to be 75°C, while the pH optimum for enzyme activity was 6.5. The specific activities of purified enolase determined at 25 and 80°C were 147 and 300 U mg(-1) of protein, respectively. K m values for the 2-phosphoglycerate/phosphoenolpyruvate reaction determined at 25 and 80°C were 0.16 and 0.03 mM, respectively. The K m values for Mg(2+) binding at these temperatures were 2.5 and 1.9 mM, respectively. When compared to enolase from mesophiles, the biochemical and structural properties of enolase from C. aurantiacus are consistent with this being thermally adapted. These data are consistent with the results of our phylogenetic analysis of enolase, which reveal that enolase has a thermophilic origin.
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Affiliation(s)
- Oleg A Zadvornyy
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA ; Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino , Russia
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University , Bozeman, MT , USA
| | - Matthew C Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines , Golden, CO , USA
| | - Nikolay A Zorin
- Institute of Basic Biological Problems, Russian Academy of Sciences , Pushchino , Russia
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, MT , USA
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4
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Baleva M, Gowher A, Kamenski P, Tarassov I, Entelis N, Masquida B. A Moonlighting Human Protein Is Involved in Mitochondrial Import of tRNA. Int J Mol Sci 2015; 16:9354-67. [PMID: 25918939 PMCID: PMC4463592 DOI: 10.3390/ijms16059354] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/02/2015] [Accepted: 04/15/2015] [Indexed: 12/29/2022] Open
Abstract
In yeast Saccharomyces cerevisiae, ~3% of the lysine transfer RNA acceptor 1 (tRK1) pool is imported into mitochondria while the second isoacceptor, tRK2, fully remains in the cytosol. The mitochondrial function of tRK1 is suggested to boost mitochondrial translation under stress conditions. Strikingly, yeast tRK1 can also be imported into human mitochondria in vivo, and can thus be potentially used as a vector to address RNAs with therapeutic anti-replicative capacity into mitochondria of sick cells. Better understanding of the targeting mechanism in yeast and human is thus critical. Mitochondrial import of tRK1 in yeast proceeds first through a drastic conformational rearrangement of tRK1 induced by enolase 2, which carries this freight to the mitochondrial pre-lysyl-tRNA synthetase (preMSK). The latter may cross the mitochondrial membranes to reach the matrix where imported tRK1 could be used by the mitochondrial translation apparatus. This work focuses on the characterization of the complex that tRK1 forms with human enolases and their role on the interaction between tRK1 and human pre-lysyl-tRNA synthetase (preKARS2).
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Affiliation(s)
- Maria Baleva
- Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, 67084 Strasbourg, France.
- Department of Molecular Biology, Biology Faculty of Moscow State University, 119992 Moscow, Russia.
| | - Ali Gowher
- Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, 67084 Strasbourg, France.
| | - Piotr Kamenski
- Department of Molecular Biology, Biology Faculty of Moscow State University, 119992 Moscow, Russia.
| | - Ivan Tarassov
- Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, 67084 Strasbourg, France.
| | - Nina Entelis
- Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, 67084 Strasbourg, France.
| | - Benoît Masquida
- Department of Molecular and Cellular Genetics, UMR 7156 Génétique Moléculaire, Génomique, Microbiologie (GMGM), CNRS-Université de Strasbourg, 67084 Strasbourg, France.
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5
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Raghunathan K, Harris PT, Spurbeck RR, Arvidson CG, Arvidson DN. Crystal structure of an efficacious gonococcal adherence inhibitor: An enolase fromLactobacillus gasseri. FEBS Lett 2014; 588:2212-6. [DOI: 10.1016/j.febslet.2014.05.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 12/01/2022]
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6
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Torsetnes SB, Løvbak SG, Claus C, Lund H, Nordlund MS, Paus E, Halvorsen TG, Reubsaet L. Immunocapture and LC–MS/MS for selective quantification and differentiation of the isozymes of the biomarker neuron-specific enolase in serum. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 929:125-32. [DOI: 10.1016/j.jchromb.2013.04.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 04/06/2013] [Accepted: 04/12/2013] [Indexed: 11/17/2022]
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7
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Qin J, Chai G, Brewer JM, Lovelace LL, Lebioda L. Structures of asymmetric complexes of human neuron specific enolase with resolved substrate and product and an analogous complex with two inhibitors indicate subunit interaction and inhibitor cooperativity. J Inorg Biochem 2012; 111:187-94. [PMID: 22437160 PMCID: PMC3371154 DOI: 10.1016/j.jinorgbio.2012.02.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/13/2012] [Accepted: 02/15/2012] [Indexed: 10/28/2022]
Abstract
In the presence of magnesium, enolase catalyzes the dehydration of 2-phospho-d-glycerate (PGA) to phosphoenolpyruvate (PEP) in glycolysis and the reverse reaction in gluconeogensis at comparable rates. The structure of human neuron specific enolase (hNSE) crystals soaked in PGA showed that the enzyme is active in the crystals and produced PEP; conversely soaking in PEP produced PGA. Moreover, the hNSE dimer contains PGA bound in one subunit and PEP or a mixture of PEP and PGA in the other. Crystals soaked in a mixture of competitive inhibitors tartronate semialdehyde phosphate (TSP) and lactic acid phosphate (LAP) showed asymmetry with TSP binding in the same site as PGA and LAP in the PEP site. Kinetic studies showed that the inhibition of NSE by mixtures of TSP and LAP is stronger than predicted for independently acting inhibitors. This indicates that in some cases inhibition of homodimeric enzymes by mixtures of inhibitors ("heteroinhibition") may offer advantages over single inhibitors.
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Affiliation(s)
- Jie Qin
- Department of Chemistry & Biochemistry, University of South Carolina, Columbia, SC 29208
| | - Geqing Chai
- Department of Chemistry & Biochemistry, University of South Carolina, Columbia, SC 29208
| | - John M. Brewer
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602
| | - Leslie L. Lovelace
- Department of Chemistry & Biochemistry, University of South Carolina, Columbia, SC 29208
| | - Lukasz Lebioda
- Department of Chemistry & Biochemistry, University of South Carolina, Columbia, SC 29208
- Center for Colon Cancer Research, University of South Carolina, Columbia, SC 29208
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8
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Schulz EC, Tietzel M, Tovy A, Ankri S, Ficner R. Structure analysis of Entamoeba histolytica enolase. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2011; 67:619-27. [PMID: 21697600 DOI: 10.1107/s0907444911016544] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Accepted: 05/02/2011] [Indexed: 11/10/2022]
Abstract
Entamoeba histolytica enolase (EhENO) reversibly interconverts 2-phosphoglyceric acid (2-PGA) and phosphoenolpyruvic acid (PEP). The crystal structure of the homodimeric EhENO is presented at a resolution of 1.9 Å. In the crystal structure EhENO presents as an asymmetric dimer with one active site in the open conformation and the other active site in the closed conformation. Interestingly, both active sites contain a copurified 2-PGA molecule. While the 2-PGA molecule in the closed active site closely resembles the conformation known from other enolase-2-PGA complexes, the conformation in the open active site is different. Here, 2-PGA is shifted approximately 1.6 Å away from metal ion I, most likely representing a precatalytic situation.
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Affiliation(s)
- Eike C Schulz
- Abteilung für Molekulare Strukturbiologie, Institut für Mikrobiologie und Genetik, Georg-August-Universität Göttingen, Justus-von-Liebig Weg, Germany.
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9
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Schreier B, Höcker B. Engineering the enolase magnesium II binding site: implications for its evolution. Biochemistry 2010; 49:7582-9. [PMID: 20690637 DOI: 10.1021/bi100954f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The glycolytic enzyme enolase catalyzes the reversible elimination of water from 2-phosphoglycerate (2-PGA) to form phosphoenolpyruvate (PEP). Two magnesium ions in the active site are thought to facilitate the reaction by activation of the C2 proton of 2-PGA and charge stabilization of the intermediate. The initial abstraction of a proton from a carboxylic acid is common to all members of the enolase superfamily, yet in all other known members of this superfamily, only one magnesium ion (MgI) per active site is sufficient to promote catalysis. We wanted to further investigate the importance of the second magnesium ion (MgII) for the catalytic mechanism of yeast enolase 1. Toward this end, we removed all MgII coordinating residues and replaced substrate-MgII interactions by introducing positively charged side chains. High-resolution crystal structures and activity assays show that the introduced positively charged side chains effectively prohibit MgII binding but fail to promote catalysis. We conclude that enolase is inactive without MgII, yet control mutants without additional positively charged side chains retain basal enolase activity through binding of magnesium to 2-PGA in an open active site without the help of MgII coordinating residues. Thus, we believe that ancestral enolase activity might have evolved in a member of the enolase superfamily that provides only the necessary catalytic residues and the binding site for MgI. Additionally, precatalytic binding of 2-PGA to the apo state of enolase was observed.
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Affiliation(s)
- Bettina Schreier
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
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10
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Brewer JM, McKinnon JS, Phillips RS. Stopped-flow studies of the reaction of d
-tartronate semialdehyde-2-phosphate with human neuronal enolase and yeast enolase 1. FEBS Lett 2010; 584:979-83. [DOI: 10.1016/j.febslet.2010.01.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 01/14/2010] [Accepted: 01/16/2010] [Indexed: 10/19/2022]
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11
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Tu SH, Chang CC, Chen CS, Tam KW, Wang YJ, Lee CH, Lin HW, Cheng TC, Huang CS, Chu JS, Shih NY, Chen LC, Leu SJ, Ho YS, Wu CH. Increased expression of enolase alpha in human breast cancer confers tamoxifen resistance in human breast cancer cells. Breast Cancer Res Treat 2009; 121:539-53. [PMID: 19655245 DOI: 10.1007/s10549-009-0492-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Accepted: 07/18/2009] [Indexed: 01/22/2023]
Abstract
Enolase-alpha (ENO-1) is a key glycolytic enzyme that has been used as a diagnostic marker to identify human lung cancers. To investigate the role of ENO-1 in breast cancer diagnosis and therapy, the mRNA levels of ENO-1 in 244 tumor and normal paired tissue samples and 20 laser capture-microdissected cell clusters were examined by quantitative real-time PCR analysis. Increased ENO-1 mRNA expression was preferentially detected in estrogen receptor-positive (ER+) tumors (tumor/normal ratio >90-fold) when compared to ER-negative (tumor/normal ratio >20-fold) tumor tissues. The data presented here demonstrate that those patients whose tumors highly expressed ENO-1 had a poor prognosis with greater tumor size (>2 cm, *P = .017), poor nodal status (N > 3, *P = .018), and a shorter disease-free interval (<==1 year, *P < .009). We also found that higher-expressing ENO-1 tumors confer longer distance relapse (tumor/normal ratio = 82.8-92.4-fold) when compared to locoregional relapse (tumor/normal ratio = 43.4-fold) in postsurgical 4-hydroxy-tamoxifen (4-OHT)-treated ER+ patients (*P = .014). These data imply that changes in tumor ENO-1 levels are related to clinical 4-OHT therapeutic outcome. In vitro studies demonstrated that decreasing ENO-1 expression using small interfering RNA (siRNA) significantly augmented 4-OHT (100 nM)-induced cytotoxicity in tamoxifen-resistant (Tam-R) breast cancer cells. These results suggest that downregulation of ENO-1 could be utilized as a novel pharmacological approach for overcoming 4-OHT resistance in breast cancer therapy.
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Affiliation(s)
- Shih-Hsin Tu
- Department of Surgery, Cathay General Hospital, Taipei, Taiwan
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12
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de A S Navarro MV, Gomes Dias SM, Mello LV, da Silva Giotto MT, Gavalda S, Blonski C, Garratt RC, Rigden DJ. Structural flexibility in Trypanosoma brucei enolase revealed by X-ray crystallography and molecular dynamics. FEBS J 2007; 274:5077-89. [PMID: 17822439 DOI: 10.1111/j.1742-4658.2007.06027.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Enolase is a validated drug target in Trypanosoma brucei. To better characterize its properties and guide drug design efforts, we have determined six new crystal structures of the enzyme, in various ligation states and conformations, and have carried out complementary molecular dynamics simulations. The results show a striking structural diversity of loops near the catalytic site, for which variation can be interpreted as distinct modes of conformational variability that are explored during the molecular dynamics simulations. Our results show that sulfate may, unexpectedly, induce full closure of catalytic site loops whereas, conversely, binding of inhibitor phosphonoacetohydroxamate may leave open a tunnel from the catalytic site to protein surface offering possibilities for drug development. We also present the first complex of enolase with a novel inhibitor 2-fluoro-2-phosphonoacetohydroxamate. The molecular dynamics results further encourage efforts to design irreversible species-specific inhibitors: they reveal that a parasite enzyme-specific lysine may approach the catalytic site more closely than crystal structures suggest and also cast light on the issue of accessibility of parasite enzyme-specific cysteines to chemically modifying reagents. One of the new sulfate structures contains a novel metal-binding site IV within the catalytic site cleft.
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13
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Szczepek M, Brondani V, Büchel J, Serrano L, Segal DJ, Cathomen T. Structure-based redesign of the dimerization interface reduces the toxicity of zinc-finger nucleases. Nat Biotechnol 2007; 25:786-93. [PMID: 17603476 DOI: 10.1038/nbt1317] [Citation(s) in RCA: 428] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Accepted: 06/04/2007] [Indexed: 11/09/2022]
Abstract
Artificial endonucleases consisting of a FokI cleavage domain tethered to engineered zinc-finger DNA-binding proteins have proven useful for stimulating homologous recombination in a variety of cell types. Because the catalytic domain of zinc-finger nucleases (ZFNs) must dimerize to become active, two subunits are typically assembled as heterodimers at the cleavage site. The use of ZFNs is often associated with significant cytotoxicity, presumably due to cleavage at off-target sites. Here we describe a structure-based approach to reducing off-target cleavage. Using in silico protein modeling and energy calculations, we increased the specificity of target site cleavage by preventing homodimerization and lowering the dimerization energy. Cell-based recombination assays confirmed that the modified ZFNs were as active as the original ZFNs but elicit significantly less genotoxicity. The improved safety profile may facilitate therapeutic application of the ZFN technology.
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Affiliation(s)
- Michal Szczepek
- Charité Medical School, Institute of Virology (CBF), 12203 Berlin, Germany
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14
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Carmieli R, Larsen TM, Reed GH, Zein S, Neese F, Goldfarb D. The catalytic Mn2+ sites in the enolase-inhibitor complex: crystallography, single-crystal EPR, and DFT calculations. J Am Chem Soc 2007; 129:4240-52. [PMID: 17367133 PMCID: PMC2538446 DOI: 10.1021/ja066124e] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Crystals of Zn2+/Mn2+ yeast enolase with the inhibitor PhAH (phosphonoacetohydroxamate) were grown under conditions with a slight preference for binding of Zn2+ at the higher affinity site, site I. The structure of the Zn2+/Mn2+-PhAH complex was solved at a resolution of 1.54 A, and the two catalytic metal binding sites, I and II, show only subtle displacement compared to that of the corresponding complex with the native Mg2+ ions. Low-temperature echo-detected high-field (W-band, 95 GHz) EPR (electron paramagnetic resonance) and 1H ENDOR (electron-nuclear double resonance) were carried out on a single crystal, and rotation patterns were acquired in two perpendicular planes. Analysis of the rotation patterns resolved a total of six Mn2+ sites, four symmetry-related sites of one type and two out of the four of the other type. The observation of two chemically inequivalent Mn2+ sites shows that Mn2+ ions populate both sites I and II and the zero-field splitting (ZFS) tensors of the Mn2+ in the two sites were determined. The Mn2+ site with the larger D value was assigned to site I based on the 1H ENDOR spectra, which identified the relevant water ligands. This assignment is consistent with the seemingly larger deviation of site I from octahedral symmetry, compared to that of site II. The ENDOR results gave the coordinates of the protons of two water ligands, and adding them to the crystal structure revealed their involvement in a network of H bonds stabilizing the binding of the metal ions and PhAH. Although specific hyperfine interactions with the inhibitor were not determined, the spectroscopic properties of the Mn2+ in the two sites were consistent with the crystal structure. Density functional theory (DFT) calculations carried out on a cluster representing the catalytic site, with Mn2+ in site I and Zn2+ in site II, and vice versa, gave overestimated D values on the order of the experimental ones, although the larger D value was found for Mn2+ in site II rather than in site I. This discrepancy was attributed to the high sensitivity of the ZFS parameters to the Mn-O bond lengths and orientations, such that small, but significant, differences between the optimized and crystal structures alter the ZFS considerably, well above the difference between the two sites.
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Affiliation(s)
- Raanan Carmieli
- Department of Chemical Physics, The Weizmann Institute of Science, Rehovot, Israel
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