51
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Kaczmarski JA, Mahawaththa MC, Feintuch A, Clifton BE, Adams LA, Goldfarb D, Otting G, Jackson CJ. Altered conformational sampling along an evolutionary trajectory changes the catalytic activity of an enzyme. Nat Commun 2020; 11:5945. [PMID: 33230119 PMCID: PMC7683729 DOI: 10.1038/s41467-020-19695-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023] Open
Abstract
Several enzymes are known to have evolved from non-catalytic proteins such as solute-binding proteins (SBPs). Although attention has been focused on how a binding site can evolve to become catalytic, an equally important question is: how do the structural dynamics of a binding protein change as it becomes an efficient enzyme? Here we performed a variety of experiments, including propargyl-DO3A-Gd(III) tagging and double electron-electron resonance (DEER) to study the rigid body protein dynamics of reconstructed evolutionary intermediates to determine how the conformational sampling of a protein changes along an evolutionary trajectory linking an arginine SBP to a cyclohexadienyl dehydratase (CDT). We observed that primitive dehydratases predominantly populate catalytically unproductive conformations that are vestiges of their ancestral SBP function. Non-productive conformational states, including a wide-open state, are frozen out of the conformational landscape via remote mutations, eventually leading to extant CDT that exclusively samples catalytically relevant compact states. These results show that remote mutations can reshape the global conformational landscape of an enzyme as a mechanism for increasing catalytic activity.
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Affiliation(s)
- Joe A Kaczmarski
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Mithun C Mahawaththa
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia
| | - Akiva Feintuch
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Ben E Clifton
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia.,Protein Engineering and Evolution Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Okinawa, 904-0412, Japan
| | - Luke A Adams
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel.
| | - Gottfried Otting
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia. .,Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia.
| | - Colin J Jackson
- Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia. .,Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia. .,Australian Research Council Centre of Excellence in Synthetic Biology, Research School of Chemistry, Australian National University, Canberra, 2601, ACT, Australia.
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52
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Eck T, Patel S, Candela T, Leon H K, Little M, Reis NE, Liyanagunawardana U, Gubler U, Janson CA, Catalano J, Goodey NM. Mutational analysis confirms the presence of distal inhibitor-selectivity determining residues in B. stearothermophilus dihydrofolate reductase. Arch Biochem Biophys 2020; 692:108545. [PMID: 32810476 PMCID: PMC10727455 DOI: 10.1016/j.abb.2020.108545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/08/2020] [Accepted: 08/12/2020] [Indexed: 11/20/2022]
Abstract
Many antibacterial and antiparasitic drugs work by competitively inhibiting dihydrofolate reductase (DHFR), a vital enzyme in folate metabolism. The interactions between inhibitors and DHFR active site residues are known in many homologs but the contributions from distal residues are less understood. Identifying distal residues that aid in inhibitor binding can improve targeted drug development programs by accounting for distant influences that may be less conserved and subject to frequent resistance causing mutations. Previously, a novel, homology-based, computational approach that mines ligand inhibition data was used to predict residues involved in inhibitor selectivity in the DHFR family. Expectedly, some inhibitor selectivity determining residue positions were predicted to lie in the active site and coincide with experimentally known inhibitor selectivity determining positions. However, other residues that group spatially in clusters distal to the active site have not been previously investigated. In this study, the effect of introducing amino acid substitutions at one of these predicted clusters (His38-Ala39-Ile40) on the inhibitor selectivity profile in Bacillus stearothermophilus dihydrofolate reductase (Bs DHFR) was investigated. Mutations were introduced into these cluster positions to change sidechain chemistry and size. We determined kcat and KM values and measured KD values at equilibrium for two competitive DHFR inhibitors, trimethoprim (TMP) and pyrimethamine (PYR). Mutations in the His38-Ala39-Ile40 cluster significantly impacted inhibitor binding and TMP/PYR selectivity - seven out of nine mutations resulted in tighter binding to PYR when compared to TMP. These data suggest that the His38-Ala39-Ile40 cluster is a distal inhibitor selectivity determining region that favors PYR binding in Bs DHFR and, possibly, throughout the DHFR family.
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Affiliation(s)
- Tyler Eck
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Seema Patel
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Thomas Candela
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Katherine Leon H
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Michael Little
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Natalia E Reis
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | | | - Ueli Gubler
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Cheryl A Janson
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Jaclyn Catalano
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA
| | - Nina M Goodey
- Dept. of Chemistry & Biochemistry, Montclair State University, Montclair, NJ, 07043, USA.
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53
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Torgeson KR, Clarkson MW, Kumar GS, Page R, Peti W. Cooperative dynamics across distinct structural elements regulate PTP1B activity. J Biol Chem 2020; 295:13829-13837. [PMID: 32737198 DOI: 10.1074/jbc.ra120.014652] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/30/2020] [Indexed: 12/14/2022] Open
Abstract
Protein-tyrosine phosphatase 1B (PTP1B) is the canonical enzyme for investigating how distinct structural elements influence enzyme catalytic activity. Although it is recognized that dynamics are essential for PTP1B function, the data collected thus far have not resolved whether distinct elements are dynamically coordinated or, alternatively, whether they fulfill their respective functions independently. To answer this question, we performed a comprehensive 13C-methyl relaxation study of Ile, Leu, and Val (ILV) residues of PTP1B, which, because of its substantially increased sensitivity, provides a comprehensive understanding of the influence of protein motions on different time scales for enzyme function. We discovered that PTP1B exhibits dynamics at three distinct time scales. First, it undergoes a distinctive slow motion that allows for the dynamic binding and release of its two most N-terminal helices from the catalytic core. Second, we showed that PTP1B 13C-methyl group side chain fast time-scale dynamics and 15N backbone fast time-scale dynamics are fully consistent, demonstrating that fast fluctuations are essential for the allosteric control of PTP1B activity. Third, and most importantly, using 13C ILV constant-time Carr-Purcell-Meiboom-Gill relaxation measurements experiments, we demonstrated that all four catalytically important loops-the WPD, Q, E, and substrate-binding loops-work in dynamic unity throughout the catalytic cycle of PTP1B. Thus, these data show that PTP1B activity is not controlled by a single functional element, but instead all key elements are dynamically coordinated. Together, these data provide the first fully comprehensive picture on how the validated drug target PTP1B functions.
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Affiliation(s)
- Kristiane R Torgeson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Michael W Clarkson
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Ganesan Senthil Kumar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona, USA.
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54
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Schober AF, Mathis AD, Ingle C, Park JO, Chen L, Rabinowitz JD, Junier I, Rivoire O, Reynolds KA. A Two-Enzyme Adaptive Unit within Bacterial Folate Metabolism. Cell Rep 2020; 27:3359-3370.e7. [PMID: 31189117 DOI: 10.1016/j.celrep.2019.05.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 04/05/2019] [Accepted: 05/09/2019] [Indexed: 11/29/2022] Open
Abstract
Enzyme function and evolution are influenced by the larger context of a metabolic pathway. Deleterious mutations or perturbations in one enzyme can often be compensated by mutations to others. We used comparative genomics and experiments to examine evolutionary interactions with the essential metabolic enzyme dihydrofolate reductase (DHFR). Analyses of synteny and co-occurrence across bacterial species indicate that DHFR is coupled to thymidylate synthase (TYMS) but relatively independent from the rest of folate metabolism. Using quantitative growth rate measurements and forward evolution in Escherichia coli, we demonstrate that the two enzymes adapt as a relatively independent unit in response to antibiotic stress. Metabolomic profiling revealed that TYMS activity must not exceed DHFR activity to prevent the depletion of reduced folates and the accumulation of the intermediate dihydrofolate. Comparative genomics analyses identified >200 gene pairs with similar statistical signatures of modular co-evolution, suggesting that cellular pathways may be decomposable into small adaptive units.
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Affiliation(s)
- Andrew F Schober
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Andrew D Mathis
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Christine Ingle
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Junyoung O Park
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Li Chen
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA; Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Ivan Junier
- Centre National de la Recherche Scientifique, Université Grenoble Alpes, TIMC-IMAG, F-38000 Grenoble, France
| | - Olivier Rivoire
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, PSL Research University, F-75005 Paris, France
| | - Kimberly A Reynolds
- The Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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55
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Kronenberger T, Ferreira GM, de Souza ADF, da Silva Santos S, Poso A, Ribeiro JA, Tavares MT, Pavan FR, Trossini GHG, Dias MVB, Parise-Filho R. Design, synthesis and biological activity of novel substituted 3-benzoic acid derivatives as MtDHFR inhibitors. Bioorg Med Chem 2020; 28:115600. [DOI: 10.1016/j.bmc.2020.115600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/02/2020] [Accepted: 06/16/2020] [Indexed: 10/24/2022]
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56
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Duff MR, Gabel SA, Pedersen LC, DeRose EF, Krahn JM, Howell EE, London RE. The Structural Basis for Nonsteroidal Anti-Inflammatory Drug Inhibition of Human Dihydrofolate Reductase. J Med Chem 2020; 63:8314-8324. [PMID: 32658475 DOI: 10.1021/acs.jmedchem.0c00546] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although nonsteroidal anti-inflammatory drugs (NSAIDs) target primarily cyclooxygenase enzymes, a subset of NSAIDs containing carboxylate groups also has been reported to competitively inhibit dihydrofolate reductase (DHFR). In this study, we have characterized NSAID interactions with human DHFR based on kinetic, NMR, and X-ray crystallographic methods. The NSAIDs target a region of the folate binding site that interacts with the p-aminobenzoyl-l-glutamate (pABG) moiety of folate and inhibit cooperatively with ligands that target the adjacent pteridine-recognition subsite. NSAIDs containing benzoate or salicylate groups were identified as having the highest potency. Among those tested, diflunisal, a salicylate derivative not previously identified to have anti-folate activity, was found to have a Ki of 34 μM, well below peak plasma diflunisal levels reached at typical dosage levels. The potential of these drugs to interfere with the inflammatory process by multiple pathways introduces the possibility of further optimization to design dual-targeted analogs.
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Affiliation(s)
- Michael R Duff
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Scott A Gabel
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Lars C Pedersen
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Eugene F DeRose
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Juno M Krahn
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
| | - Elizabeth E Howell
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Robert E London
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, Durham, North Carolina 27709, United States
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57
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Adesina AS, Świderek K, Luk LYP, Moliner V, Allemann RK. Electric Field Measurements Reveal the Pivotal Role of Cofactor-Substrate Interaction in Dihydrofolate Reductase Catalysis. ACS Catal 2020; 10:7907-7914. [PMID: 32905264 PMCID: PMC7467645 DOI: 10.1021/acscatal.0c01856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/18/2020] [Indexed: 12/31/2022]
Abstract
![]()
The
contribution of ligand–ligand electrostatic interaction
to transition state formation during enzyme catalysis has remained
unexplored, even though electrostatic forces are known to play a major
role in protein functions and have been investigated by the vibrational
Stark effect (VSE). To monitor electrostatic changes along important
steps during catalysis, we used a nitrile probe (T46C-CN) inserted
proximal to the reaction center of three dihydrofolate reductases
(DHFRs) with different biophysical properties, Escherichia
coli DHFR (EcDHFR), its conformationally impaired variant
(EcDHFR-S148P), and Geobacillus stearothermophilus DHFR (BsDHFR). Our combined experimental and computational approach
revealed that the electric field projected by the substrate toward
the probe negates those exerted by the cofactor when both are bound
within the enzymes. This indicates that compared to previous models
that focus exclusively on subdomain reorganization and protein–ligand
contacts, ligand–ligand interactions are the key driving force
to generate electrostatic environments conducive for catalysis.
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Affiliation(s)
- Aduragbemi S. Adesina
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Katarzyna Świderek
- Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castellón, Spain
| | - Louis Y. P. Luk
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Vicent Moliner
- Departament de Química Física i Analítica, Universitat Jaume I, 12071 Castellón, Spain
| | - Rudolf K. Allemann
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, United Kingdom
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58
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Crean RM, Gardner JM, Kamerlin SCL. Harnessing Conformational Plasticity to Generate Designer Enzymes. J Am Chem Soc 2020; 142:11324-11342. [PMID: 32496764 PMCID: PMC7467679 DOI: 10.1021/jacs.0c04924] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Indexed: 02/08/2023]
Abstract
Recent years have witnessed an explosion of interest in understanding the role of conformational dynamics both in the evolution of new enzymatic activities from existing enzymes and in facilitating the emergence of enzymatic activity de novo on scaffolds that were previously non-catalytic. There are also an increasing number of examples in the literature of targeted engineering of conformational dynamics being successfully used to alter enzyme selectivity and activity. Despite the obvious importance of conformational dynamics to both enzyme function and evolvability, many (although not all) computational design approaches still focus either on pure sequence-based approaches or on using structures with limited flexibility to guide the design. However, there exist a wide variety of computational approaches that can be (re)purposed to introduce conformational dynamics as a key consideration in the design process. Coupled with laboratory evolution and more conventional existing sequence- and structure-based approaches, these techniques provide powerful tools for greatly expanding the protein engineering toolkit. This Perspective provides an overview of evolutionary studies that have dissected the role of conformational dynamics in facilitating the emergence of novel enzymes, as well as advances in computational approaches that allow one to target conformational dynamics as part of enzyme design. Harnessing conformational dynamics in engineering studies is a powerful paradigm with which to engineer the next generation of designer biocatalysts.
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Affiliation(s)
- Rory M. Crean
- Department of Chemistry -
BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Jasmine M. Gardner
- Department of Chemistry -
BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Shina C. L. Kamerlin
- Department of Chemistry -
BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
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59
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Allostery and Epistasis: Emergent Properties of Anisotropic Networks. ENTROPY 2020; 22:e22060667. [PMID: 33286439 PMCID: PMC7517209 DOI: 10.3390/e22060667] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 11/17/2022]
Abstract
Understanding the underlying mechanisms behind protein allostery and non-additivity of substitution outcomes (i.e., epistasis) is critical when attempting to predict the functional impact of mutations, particularly at non-conserved sites. In an effort to model these two biological properties, we extend the framework of our metric to calculate dynamic coupling between residues, the Dynamic Coupling Index (DCI) to two new metrics: (i) EpiScore, which quantifies the difference between the residue fluctuation response of a functional site when two other positions are perturbed with random Brownian kicks simultaneously versus individually to capture the degree of cooperativity of these two other positions in modulating the dynamics of the functional site and (ii) DCIasym, which measures the degree of asymmetry between the residue fluctuation response of two sites when one or the other is perturbed with a random force. Applied to four independent systems, we successfully show that EpiScore and DCIasym can capture important biophysical properties in dual mutant substitution outcomes. We propose that allosteric regulation and the mechanisms underlying non-additive amino acid substitution outcomes (i.e., epistasis) can be understood as emergent properties of an anisotropic network of interactions where the inclusion of the full network of interactions is critical for accurate modeling. Consequently, mutations which drive towards a new function may require a fine balance between functional site asymmetry and strength of dynamic coupling with the functional sites. These two tools will provide mechanistic insight into both understanding and predicting the outcome of dual mutations.
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60
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Liang Y, Song H, Wu M, Xie Y, Gu X, He R, Lai W, Jing B, Peng X, Yang G. Preliminary Evaluation of Recombinant EPC1 and TPx for Serological Diagnosis of Animal Cystic Echinococcosis. Front Cell Infect Microbiol 2020; 10:177. [PMID: 32426296 PMCID: PMC7203340 DOI: 10.3389/fcimb.2020.00177] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/03/2020] [Indexed: 11/13/2022] Open
Abstract
Animal cystic echinococcosis (CE) is one of the most important helminthic diseases and affects many mammalian intermediate hosts. Practical and effective diagnosis is crucial for animal CE control. Two different recombinant antigens derived from Echinococcus granulosus, Echinococcus protoscolex calcium binding protein 1 (rEg-EPC1) and thioredoxin peroxidase (rEg-TPx), were evaluated in this study to detect the specific immunoglobulin G (IgG) in sheep and goat with CE by the indirect enzyme-linked immunosorbent assays. The diagnostic effect of the above-listed proteins was determined to their sensitivity and specificity and compared with hydatid cyst fluid, two previously reported immunogenic recombinant proteins (dihydrofolate reductase and P29), and two commercial kits available in China. Of these, the best diagnostic results were obtained in the anti-TPx IgG ELISA, with 92.6% sensitivity, 98.8% specificity, and no cross-reactivity with anti-Eg95 IgG. Recombinant E. granulosus thioredoxin peroxidase shows good potential for serological diagnosis of animal cystic echinococcosis.
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Affiliation(s)
- Yuqing Liang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Hongyu Song
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Maodi Wu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xiaobin Gu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Ran He
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Weiming Lai
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Bo Jing
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
| | - Xuerong Peng
- Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Chengdu, China
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China
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61
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Vallejos-Vidal E, Reyes-Cerpa S, Rivas-Pardo JA, Maisey K, Yáñez JM, Valenzuela H, Cea PA, Castro-Fernandez V, Tort L, Sandino AM, Imarai M, Reyes-López FE. Single-Nucleotide Polymorphisms (SNP) Mining and Their Effect on the Tridimensional Protein Structure Prediction in a Set of Immunity-Related Expressed Sequence Tags (EST) in Atlantic Salmon ( Salmo salar). Front Genet 2020; 10:1406. [PMID: 32174954 PMCID: PMC7056891 DOI: 10.3389/fgene.2019.01406] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 12/24/2019] [Indexed: 12/12/2022] Open
Abstract
Single-nucleotide polymorphisms (SNPs) are single genetic code variations considered one of the most common forms of nucleotide modifications. Such SNPs can be located in genes associated to immune response and, therefore, they may have direct implications over the phenotype of susceptibility to infections affecting the productive sector. In this study, a set of immune-related genes (cc motif chemokine 19 precursor [ccl19], integrin β2 (itβ2, also named cd18), glutathione transferase omega-1 [gsto-1], heat shock 70 KDa protein [hsp70], major histocompatibility complex class I [mhc-I]) were analyzed to identify SNPs by data mining. These genes were chosen based on their previously reported expression on infectious pancreatic necrosis virus (IPNV)-infected Atlantic salmon phenotype. The available EST sequences for these genes were obtained from the Unigene database. Twenty-eight SNPs were found in the genes evaluated and identified most of them as transition base changes. The effect of the SNPs located on the 5'-untranslated region (UTR) or 3'-UTR upon transcription factor binding sites and alternative splicing regulatory motifs was assessed and ranked with a low-medium predicted FASTSNP score risk. Synonymous SNPs were found on itβ2 (c.2275G > A), gsto-1 (c.558G > A), and hsp70 (c.1950C > T) with low FASTSNP predicted score risk. The difference in the relative synonymous codon usage (RSCU) value between the variant codons and the wild-type codon (ΔRSCU) showed one negative (hsp70 c.1950C > T) and two positive ΔRSCU values (itβ2 c.2275G > A; gsto-1 c.558G > A), suggesting that these synonymous SNPs (sSNPs) may be associated to differences in the local rate of elongation. Nonsynonymous SNPs (nsSNPs) in the gsto-1 translatable gene region were ranked, using SIFT and POLYPHEN web-tools, with the second highest (c.205A > G; c484T > C) and the highest (c.499T > C; c.769A > C) predicted score risk possible. Using homology modeling to predict the effect of these nonsynonymous SNPs, the most relevant nucleotide changes for gsto-1 were observed for the nsSNPs c.205A > G, c484T > C, and c.769A > C. Molecular dynamics was assessed to analyze if these GSTO-1 variants have significant differences in their conformational dynamics, suggesting these SNPs could have allosteric effects modulating its catalysis. Altogether, these results suggest that candidate SNPs identified may play a crucial potential role in the immune response of Atlantic salmon.
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Affiliation(s)
- Eva Vallejos-Vidal
- Department of Cell Biology, Physiology and Immunology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sebastián Reyes-Cerpa
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Jaime Andrés Rivas-Pardo
- Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Kevin Maisey
- Centro de Biotecnología Acuícola, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - José M. Yáñez
- Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Hector Valenzuela
- Centro de Biotecnología Acuícola, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Pablo A. Cea
- Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | | | - Lluis Tort
- Department of Cell Biology, Physiology and Immunology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Ana M. Sandino
- Centro de Biotecnología Acuícola, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Mónica Imarai
- Centro de Biotecnología Acuícola, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Felipe E. Reyes-López
- Department of Cell Biology, Physiology and Immunology, Faculty of Biosciences, Universitat Autònoma de Barcelona, Barcelona, Spain
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62
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Campitelli P, Modi T, Kumar S, Ozkan SB. The Role of Conformational Dynamics and Allostery in Modulating Protein Evolution. Annu Rev Biophys 2020; 49:267-288. [PMID: 32075411 DOI: 10.1146/annurev-biophys-052118-115517] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Advances in sequencing techniques and statistical methods have made it possible not only to predict sequences of ancestral proteins but also to identify thousands of mutations in the human exome, some of which are disease associated. These developments have motivated numerous theories and raised many questions regarding the fundamental principles behind protein evolution, which have been traditionally investigated horizontally using the tip of the phylogenetic tree through comparative studies of extant proteins within a family. In this article, we review a vertical comparison of the modern and resurrected ancestral proteins. We focus mainly on the dynamical properties responsible for a protein's ability to adapt new functions in response to environmental changes. Using the Dynamic Flexibility Index and the Dynamic Coupling Index to quantify the relative flexibility and dynamic coupling at a site-specific, single-amino-acid level, we provide evidence that the migration of hinges, which are often functionally critical rigid sites, is a mechanism through which proteins can rapidly evolve. Additionally, we show that disease-associated mutations in proteins often result in flexibility changes even at positions distal from mutational sites, particularly in the modulation of active site dynamics.
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Affiliation(s)
- Paul Campitelli
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona 85281, USA; , ,
| | - Tushar Modi
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona 85281, USA; , ,
| | - Sudhir Kumar
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, Pennsylvania 19122, USA; .,Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, USA.,Center for Excellence in Genome Medicine and Research, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - S Banu Ozkan
- Center for Biological Physics, Department of Physics, Arizona State University, Tempe, Arizona 85281, USA; , ,
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63
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Highly Contingent Phenotypes of Lon Protease Deficiency in Escherichia coli upon Antibiotic Challenge. J Bacteriol 2020; 202:JB.00561-19. [PMID: 31740490 DOI: 10.1128/jb.00561-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/05/2019] [Indexed: 01/05/2023] Open
Abstract
Evolutionary trajectories and mutational landscapes of drug-resistant bacteria are influenced by cell-intrinsic and extrinsic factors. In this study, I demonstrated that loss of the Lon protease altered susceptibility of Escherichia coli to trimethoprim and that these effects were strongly contingent on the drug concentration and genetic background. Lon, an AAA+ ATPase, is a bacterial master regulator protease involved in cytokinesis, suppression of transposition events, and clearance of misfolded proteins. I show that Lon deficiency enhances intrinsic drug tolerance at sub-MIC levels of trimethoprim. As a result, loss of Lon, though disadvantageous under drug-free conditions, has a selective advantage at low concentrations of trimethoprim. At high drug concentrations, however, Lon deficiency is detrimental for E. coli I show that the former is explained by suppression of drug efflux by Lon, while the latter can be attributed to SulA-dependent hyperfilamentation. On the other hand, deletion of lon in a trimethoprim-resistant mutant E. coli strain (harboring the Trp30Gly dihydrofolate reductase [DHFR] allele) directly potentiates resistance by enhancing the in vivo stability of mutant DHFR. Using extensive mutational analysis at 3 hot spots of resistance, I show that many resistance-conferring mutations render DHFR prone to proteolysis. This trade-off between gaining resistance and losing in vivo stability limits the number of mutations in DHFR that can confer trimethoprim resistance. Loss of Lon expands the mutational capacity for acquisition of trimethoprim resistance. This paper identifies the multipronged action of Lon in trimethoprim resistance in E. coli and provides mechanistic insight into how genetic backgrounds and drug concentrations may alter the potential for antimicrobial resistance evolution.IMPORTANCE Understanding the evolutionary dynamics of antimicrobial resistance is vital to curb its emergence and spread. Being fundamentally similar to natural selection, the fitness of resistant mutants is a key parameter to consider in the evolutionary dynamics of antimicrobial resistance (AMR). Various intrinsic and extrinsic factors modulate the fitness of resistant bacteria. This study demonstrated that Lon, a bacterial master regulator protease, influences drug tolerance and resistance. Lon is a key regulator of several fundamental processes in bacteria, including cytokinesis. I demonstrated that Lon deficiency produces highly contingent phenotypes in E. coli challenged with trimethoprim and can expand the mutational repertoire available to E. coli to evolve resistance. This multipronged influence of Lon on drug resistance provides an illustrative instance of how master regulators shape the response of bacteria to antibiotics.
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64
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Yang K, Arai M, Wright PE. Determining Binding Kinetics of Intrinsically Disordered Proteins by NMR Spectroscopy. Methods Mol Biol 2020; 2141:663-681. [PMID: 32696383 PMCID: PMC7605514 DOI: 10.1007/978-1-0716-0524-0_34] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The unique structural flexibility of intrinsically disordered proteins (IDPs) is central to their diverse functions in cellular processes. Protein-protein interactions involving IDPs are frequently transient and dynamic in nature. Nuclear magnetic resonance (NMR) spectroscopy is an especially powerful tool for characterizing the structural propensities, dynamics, and interactions of IDPs. Here we describe applications of the Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion experiment in combination with NMR titrations to characterize the kinetics and mechanisms of interactions between intrinsically disordered proteins and their targets. We illustrate the method with reference to interactions between the activation domain of the human T-cell leukemia virus type-I (HTLV-1) basic leucine zipper protein (HBZ) and its cellular binding partner, the KIX domain of the transcriptional coactivator CBP.
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Affiliation(s)
- Ke Yang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA
| | - Munehito Arai
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, USA.
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65
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Damry AM, Mayer MM, Broom A, Goto NK, Chica RA. Origin of conformational dynamics in a globular protein. Commun Biol 2019; 2:433. [PMID: 31799435 PMCID: PMC6879633 DOI: 10.1038/s42003-019-0681-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 11/06/2019] [Indexed: 11/28/2022] Open
Abstract
Protein structures are dynamic, undergoing motions that can play a vital role in function. However, the link between primary sequence and conformational dynamics remains poorly understood. Here, we studied how conformational dynamics can arise in a globular protein by evaluating the impact of individual core-residue substitutions in DANCER-3, a streptococcal protein G domain β1 variant that we previously designed to undergo a specific mode of conformational exchange that has never been observed in the wild-type protein. Using a combination of solution NMR experiments and molecular dynamics simulations, we demonstrate that only two mutations are necessary to create this conformational exchange, and that these mutations work synergistically, with one destabilizing the native structure and the other allowing two new conformational states to be accessed on the energy landscape. Overall, our results show how dynamics can appear in a stable globular fold, a critical step in the molecular evolution of dynamics-linked functions.
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Affiliation(s)
- Adam M. Damry
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5
| | - Marc M. Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5
| | - Aron Broom
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5
| | - Natalie K. Goto
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5
| | - Roberto A. Chica
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5
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66
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Singh H, Kaur M, Kaur H, Sharma I, Bhandari A, Kaur G, Singh P. Structural tuning of acridones for developing anticancer agents targeting dihydrofolate reductase. Bioorg Med Chem Lett 2019; 29:126631. [PMID: 31447082 DOI: 10.1016/j.bmcl.2019.126631] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 11/25/2022]
Abstract
Targeting dihydrofolate reductase, here, we report the tumor growth inhibitory activity of substituted acridones. The screening of the molecules over 60 cell line panel of human cancer cells identified (S)-oxiran-2-ylmethyl 9-oxo-9,10-dihydroacridine-4-carboxylate (19) with average GI50 0.3 μM. The specificity of the compound to CCRF-CEM, MOLT-4 and SR cell lines of leukemia and SW-620, SF268, LOXIMVI, ACHN and MCF7 cancerous cells exhibiting GI50 in the nM range was observed. C6 Glioma cells treated with compound 19 showed differentiated cell morphology and cell cycle arrest in G2/M phase. The interactions of the compound with dihydrofolate reductase were ascertained with the help of enzyme immunoassays, molecular docking and molecular dynamic studies.
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Affiliation(s)
- Harpreet Singh
- Department of Chemistry, UGC Sponsored Centre for Advanced Studies, Guru Nanak Dev University, Amritsar 143005, India
| | - Manpreet Kaur
- Department of Chemistry, UGC Sponsored Centre for Advanced Studies, Guru Nanak Dev University, Amritsar 143005, India
| | - Harpreet Kaur
- Department of Chemistry, UGC Sponsored Centre for Advanced Studies, Guru Nanak Dev University, Amritsar 143005, India
| | - Indu Sharma
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, India
| | - Anmol Bhandari
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, India
| | - Gurcharan Kaur
- Department of Biotechnology, Guru Nanak Dev University, Amritsar 143005, India
| | - Palwinder Singh
- Department of Chemistry, UGC Sponsored Centre for Advanced Studies, Guru Nanak Dev University, Amritsar 143005, India.
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67
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Ribeiro JA, Chavez-Pacheco SM, de Oliveira GS, Silva CDS, Giudice JHP, Libreros-Zúñiga GA, Dias MVB. Crystal structures of the closed form of Mycobacterium tuberculosis dihydrofolate reductase in complex with dihydrofolate and antifolates. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:682-693. [PMID: 31282477 DOI: 10.1107/s205979831900901x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 06/24/2019] [Indexed: 12/19/2022]
Abstract
Tuberculosis is a disease caused by Mycobacterium tuberculosis and is the leading cause of death from a single infectious pathogen, with a high prevalence in developing countries in Africa and Asia. There still is a need for the development or repurposing of novel therapies to combat this disease owing to the long-term nature of current therapies and because of the number of reported resistant strains. Here, structures of dihydrofolate reductase from M. tuberculosis (MtDHFR), which is a key target of the folate pathway, are reported in complex with four antifolates, pyrimethamine, cycloguanil, diaverdine and pemetrexed, and its substrate dihydrofolate in order to understand their binding modes. The structures of all of these complexes were obtained in the closed-conformation state of the enzyme and a fine structural analysis indicated motion in key regions of the substrate-binding site and different binding modes of the ligands. In addition, the affinities, through Kd measurement, of diaverdine and methotrexate have been determined; MtDHFR has a lower affinity (highest Kd) for diaverdine than pyrimethamine and trimethoprim, and a very high affinity for methotrexate, as expected. The structural comparisons and analysis described in this work provide new information about the plasticity of MtDHFR and the binding effects of different antifolates.
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Affiliation(s)
- João Augusto Ribeiro
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Sair Maximo Chavez-Pacheco
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Gabriel Stephani de Oliveira
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Catharina Dos Santos Silva
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - João Henrique Pimenta Giudice
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Gerardo Andres Libreros-Zúñiga
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
| | - Marcio Vinicius Bertacine Dias
- Department of Microbiology, Institute of Biomedical Science, University of São Paulo, Avenida Professor Lineu Prestes 1374, São Paulo 05508-000, Brazil
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68
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Consensus sequence design as a general strategy to create hyperstable, biologically active proteins. Proc Natl Acad Sci U S A 2019; 116:11275-11284. [PMID: 31110018 DOI: 10.1073/pnas.1816707116] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Consensus sequence design offers a promising strategy for designing proteins of high stability while retaining biological activity since it draws upon an evolutionary history in which residues important for both stability and function are likely to be conserved. Although there have been several reports of successful consensus design of individual targets, it is unclear from these anecdotal studies how often this approach succeeds and how often it fails. Here, we attempt to assess generality by designing consensus sequences for a set of six protein families with a range of chain lengths, structures, and activities. We characterize the resulting consensus proteins for stability, structure, and biological activities in an unbiased way. We find that all six consensus proteins adopt cooperatively folded structures in solution. Strikingly, four of six of these consensus proteins show increased thermodynamic stability over naturally occurring homologs. Each consensus protein tested for function maintained at least partial biological activity. Although peptide binding affinity by a consensus-designed SH3 is rather low, K m values for consensus enzymes are similar to values from extant homologs. Although consensus enzymes are slower than extant homologs at low temperature, they are faster than some thermophilic enzymes at high temperature. An analysis of sequence properties shows consensus proteins to be enriched in charged residues, and rarified in uncharged polar residues. Sequence differences between consensus and extant homologs are predominantly located at weakly conserved surface residues, highlighting the importance of these residues in the success of the consensus strategy.
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69
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Wang M, Hu T, Xie KY. Dihydrofolate reductase as a predictor for poor response to platinum-based chemotherapy in epithelial ovarian cancer. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2019; 12:1723-1730. [PMID: 31933990 PMCID: PMC6947109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 02/22/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Platinum-based chemotherapy is the first line chemotherapy regimen for ovarian cancer patients. However, chemotherapy resistance is observed in a large proportion of patients. It is urgently needed to investigate prognostic biomarkers for chemo-sensitivity in ovarian cancer. METHODS Dihydrofolate reductase (DHFR) expression was measured by immunohistochemical staining in 108 specimens, as well as DHFR mRNA variants with qRT-PCR assays. The correlation between DHFR expression and platinum-based chemotherapy response was analyzed. The prognostic significance of DHFR expression was evaluated in ovarian cancer. RESULTS Positive DHFR expression was observed in 48 specimens, which was correlated to chemotherapy resistance in ovarian cancer patients. Elevated DHFR2 mRNA expression, rather than DHFR1, was observed in chemotherapy resistant tumors. Positive DHFR expression was correlated with higher histologic grade in ovarian cancer (P = 0.014). Kaplan-Meier analysis indicated that DHFR positive expression predicted poor disease-free survival (DFS) (P = 0.040), but not overall survival (OS) of ovarian cancer patients (P = 0.706). The prognostic value was further supported by TCGA data analysis. Cox regression analysis indicated that positive DHFR expression was an independent detrimental factor for disease progression for ovarian cancer patients (P = 0.016). CONCLUSION DHFR level measurement was a valuable prognostic biomarker for chemo-sensitivity of ovarian cancer. Molecular analysis for DHFR variants will provide important evidence for chemotherapy regimen options.
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Affiliation(s)
- Min Wang
- Department of Obstetrics and Gynecology, Second People’s Hospital of ChengduChengdu 610047, Sichuan, China
| | - Ting Hu
- Department of Obstetrics and Gynecology, Second People’s Hospital of ChengduChengdu 610047, Sichuan, China
| | - Ke-Yu Xie
- Department of Anesthesia, Second People’s Hospital of ChengduChengdu 610047, Sichuan, China
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70
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The Structural Dynamics of Engineered β-Lactamases Vary Broadly on Three Timescales yet Sustain Native Function. Sci Rep 2019; 9:6656. [PMID: 31040324 PMCID: PMC6491436 DOI: 10.1038/s41598-019-42866-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 04/10/2019] [Indexed: 12/20/2022] Open
Abstract
Understanding the principles of protein dynamics will help guide engineering of protein function: altering protein motions may be a barrier to success or may be an enabling tool for protein engineering. The impact of dynamics on protein function is typically reported over a fraction of the full scope of motional timescales. If motional patterns vary significantly at different timescales, then only by monitoring motions broadly will we understand the impact of protein dynamics on engineering functional proteins. Using an integrative approach combining experimental and in silico methodologies, we elucidate protein dynamics over the entire span of fast to slow timescales (ps to ms) for a laboratory-engineered system composed of five interrelated β-lactamases: two natural homologs and three laboratory-recombined variants. Fast (ps-ns) and intermediate (ns-µs) dynamics were mostly conserved. However, slow motions (µs-ms) were few and conserved in the natural homologs yet were numerous and widely dispersed in their recombinants. Nonetheless, modified slow dynamics were functionally tolerated. Crystallographic B-factors from high-resolution X-ray structures were partly predictive of the conserved motions but not of the new slow motions captured in our solution studies. Our inspection of protein dynamics over a continuous range of timescales vividly illustrates the complexity of dynamic impacts of protein engineering as well as the functional tolerance of an engineered enzyme system to new slow motions.
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71
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Niessen KA, Xu M, George DK, Chen MC, Ferré-D'Amaré AR, Snell EH, Cody V, Pace J, Schmidt M, Markelz AG. Protein and RNA dynamical fingerprinting. Nat Commun 2019; 10:1026. [PMID: 30833555 PMCID: PMC6399446 DOI: 10.1038/s41467-019-08926-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 02/04/2019] [Indexed: 01/30/2023] Open
Abstract
Protein structural vibrations impact biology by steering the structure to functional intermediate states; enhancing tunneling events; and optimizing energy transfer. Strong water absorption and a broad continuous vibrational density of states have prevented optical identification of these vibrations. Recently spectroscopic signatures that change with functional state were measured using anisotropic terahertz microscopy. The technique however has complex sample positioning requirements and long measurement times, limiting access for the biomolecular community. Here we demonstrate that a simplified system increases spectroscopic structure to dynamically fingerprint biomacromolecules with a factor of 6 reduction in data acquisition time. Using this technique, polarization varying anisotropy terahertz microscopy, we show sensitivity to inhibitor binding and unique vibrational spectra for several proteins and an RNA G-quadruplex. The technique’s sensitivity to anisotropic absorbance and birefringence provides rapid assessment of macromolecular dynamics that impact biology. The characterization of biomacromolecule structural vibrations has been impeded by a broad continuous vibrational density of states obscuring molecule specific vibrations. A terahertz microscopy system using polarization control produces signatures to dynamically fingerprint proteins and a RNA G-quadruplex.
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Affiliation(s)
| | - Mengyang Xu
- Department of Physics, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Deepu K George
- Department of Physics, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Michael C Chen
- National Heart, Lung and Blood Institute, Bethesda, MD, USA
| | | | - Edward H Snell
- Hauptman-Woodward Medical Research Institute & Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Vivian Cody
- Hauptman-Woodward Medical Research Institute & Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - James Pace
- Hauptman-Woodward Medical Research Institute & Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA
| | - Marius Schmidt
- Department of Physics, University of Wisconsin, Milwaukee, WI, USA
| | - Andrea G Markelz
- Department of Physics, University at Buffalo, SUNY, Buffalo, NY, USA. .,Hauptman-Woodward Medical Research Institute & Department of Structural Biology, University at Buffalo, SUNY, Buffalo, NY, USA.
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72
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The crystal structure of a tetrahydrofolate-bound dihydrofolate reductase reveals the origin of slow product release. Commun Biol 2018; 1:226. [PMID: 30564747 PMCID: PMC6290769 DOI: 10.1038/s42003-018-0236-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 11/15/2018] [Indexed: 12/02/2022] Open
Abstract
Dihydrofolate reductase (DHFR) catalyzes the stereospecific reduction of 7,8-dihydrofolate (FH2) to (6s)-5,6,7,8-tetrahydrofolate (FH4) via hydride transfer from NADPH. The consensus Escherichia coli DHFR mechanism involves conformational changes between closed and occluded states occurring during the rate-limiting product release step. Although the Protein Data Bank (PDB) contains over 250 DHFR structures, the FH4 complex structure responsible for rate-limiting product release is unknown. We report to our knowledge the first crystal structure of an E. coli. DHFR:FH4 complex at 1.03 Å resolution showing distinct stabilizing interactions absent in FH2 or related (6R)-5,10-dideaza-FH4 complexes. We discover the time course of decay of the co-purified endogenous FH4 during crystal growth, with conversion from FH4 to FH2 occurring in 2–3 days. We also determine another occluded complex structure of E. coli DHFR with a slow-onset nanomolar inhibitor that contrasts with the methotrexate complex, suggesting a plausible strategy for designing DHFR antibiotics by targeting FH4 product conformations. Hongnan Cao et al. present the X-ray crystal structure of E. coli dihydrofolate reductase (DHFR) in complex with its reduced substrate, (6s)-5,6,7,8-tetrahydrofolate (FH4). This structure provides the first glimpse of the rate-limiting product release step of the DHFR mechanism and suggests a strategy for designing DHFR-targeting antibiotics.
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73
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Mhashal AR, Pshetitsky Y, Cheatum CM, Kohen A, Major DT. Evolutionary Effects on Bound Substrate pKa in Dihydrofolate Reductase. J Am Chem Soc 2018; 140:16650-16660. [DOI: 10.1021/jacs.8b09089] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Anil R. Mhashal
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yaron Pshetitsky
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | | | - Amnon Kohen
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Dan Thomas Major
- Department of Chemistry, Bar-Ilan University, Ramat-Gan 5290002, Israel
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Dashnyam P, Mudududdla R, Hsieh TJ, Lin TC, Lin HY, Chen PY, Hsu CY, Lin CH. β-Glucuronidases of opportunistic bacteria are the major contributors to xenobiotic-induced toxicity in the gut. Sci Rep 2018; 8:16372. [PMID: 30401818 PMCID: PMC6219552 DOI: 10.1038/s41598-018-34678-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 10/23/2018] [Indexed: 02/07/2023] Open
Abstract
Gut bacterial β-D-glucuronidases (GUSs) catalyze the removal of glucuronic acid from liver-produced β-D-glucuronides. These reactions can have deleterious consequences when they reverse xenobiotic metabolism. The human gut contains hundreds of GUSs of variable sequences and structures. To understand how any particular bacterial GUS(s) contributes to global GUS activity and affects human health, the individual substrate preference(s) must be known. Herein, we report that representative GUSs vary in their ability to produce various xenobiotics from their respective glucuronides. To attempt to explain the distinct substrate preference, we solved the structure of a bacterial GUS complexed with coumarin-3-β-D-glucuronide. Comparisons of this structure with other GUS structures identified differences in loop 3 (or the α2-helix loop) and loop 5 at the aglycone-binding site, where differences in their conformations, hydrophobicities and flexibilities appear to underlie the distinct substrate preference(s) of the GUSs. Additional sequence, structural and functional analysis indicated that several groups of functionally related gut bacterial GUSs exist. Our results pinpoint opportunistic gut bacterial GUSs as those that cause xenobiotic-induced toxicity. We propose a structure-activity relationship that should allow both the prediction of the functional roles of GUSs and the design of selective inhibitors.
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Affiliation(s)
- Punsaldulam Dashnyam
- 0000 0000 9360 4962grid.469086.5Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, 11529 Taiwan ,0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan ,0000 0004 0532 3749grid.260542.7Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, 40227 Taiwan
| | - Ramesh Mudududdla
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Tung-Ju Hsieh
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Ting-Chien Lin
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Hsien-Ya Lin
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Peng-Yuan Chen
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Chia-Yi Hsu
- 0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan
| | - Chun-Hung Lin
- 0000 0000 9360 4962grid.469086.5Molecular and Biological Agricultural Sciences, Taiwan International Graduate Program, Academia Sinica and National Chung-Hsing University, Taipei, 11529 Taiwan ,0000 0001 2287 1366grid.28665.3fInstitute of Biological Chemistry, Academia Sinica, Taipei, 11529 Taiwan ,0000 0004 0532 3749grid.260542.7Biotechnology Center, National Chung-Hsing University, Taichung, 40227 Taiwan ,0000 0004 0546 0241grid.19188.39Department of Chemistry and Institute of Biochemical Sciences, National Taiwan University, Taipei, 10617 Taiwan
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75
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Molecular modeling of conformational dynamics and its role in enzyme evolution. Curr Opin Struct Biol 2018; 52:50-57. [PMID: 30205262 DOI: 10.1016/j.sbi.2018.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/20/2018] [Indexed: 12/19/2022]
Abstract
With increasing computational power, biomolecular simulations have become an invaluable tool for understanding enzyme mechanisms and the origins of enzyme catalysis. More recently, computational studies have started to focus on understanding how enzyme activity itself evolves, both in terms of enhancing the native or new activities on existing enzyme scaffolds, or completely de novo on previously non-catalytic scaffolds. In this context, both experiment and molecular modeling provided strong evidence for an important role of conformational dynamics in the evolution of enzyme functions. This contribution will present a brief overview of the current state of the art for computationally exploring enzyme conformational dynamics in enzyme evolution, and, using several showcase studies, illustrate the ways molecular modeling can be used to shed light on how enzyme function evolves, at the most fundamental molecular level.
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76
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Evolutionarily Related Dihydrofolate Reductases Perform Coequal Functions Yet Show Divergence in Their Trajectories. Protein J 2018; 37:301-310. [PMID: 30019321 DOI: 10.1007/s10930-018-9784-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The enzyme dihydrofolate reductase (DHFR) catalyzes NADPH dependent reduction of dihydrofolate to tetrahydrofolate. It plays a crucial role in the DNA synthesis. The investigation of evolution of DHFR generates immense curiosity. It aids in predicting how the enzyme has adapted to the surroundings of various cell types. In spite of great similarity in the structure of E. coli DHFR and human DHFR, their primary sequences are divergent to a great extent, which is evident in variations in the kinetics mechanism of their catalysis. In presence of physiological levels of ligands, they possess distinct kinetics and different rate limiting steps. We have reviewed the process of their unfolding and refolding, their behaviour in denaturing conditions and in presence of various chaperones. Although there is structural similarity between these two homologous enzymes yet they have established distinct mechanisms to accomplish the coequal functions.
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77
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Petrović D, Risso VA, Kamerlin SCL, Sanchez-Ruiz JM. Conformational dynamics and enzyme evolution. J R Soc Interface 2018; 15:20180330. [PMID: 30021929 PMCID: PMC6073641 DOI: 10.1098/rsif.2018.0330] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 06/27/2018] [Indexed: 12/21/2022] Open
Abstract
Enzymes are dynamic entities, and their dynamic properties are clearly linked to their biological function. It follows that dynamics ought to play an essential role in enzyme evolution. Indeed, a link between conformational diversity and the emergence of new enzyme functionalities has been recognized for many years. However, it is only recently that state-of-the-art computational and experimental approaches are revealing the crucial molecular details of this link. Specifically, evolutionary trajectories leading to functional optimization for a given host environment or to the emergence of a new function typically involve enriching catalytically competent conformations and/or the freezing out of non-competent conformations of an enzyme. In some cases, these evolutionary changes are achieved through distant mutations that shift the protein ensemble towards productive conformations. Multifunctional intermediates in evolutionary trajectories are probably multi-conformational, i.e. able to switch between different overall conformations, each competent for a given function. Conformational diversity can assist the emergence of a completely new active site through a single mutation by facilitating transition-state binding. We propose that this mechanism may have played a role in the emergence of enzymes at the primordial, progenote stage, where it was plausibly promoted by high environmental temperatures and the possibility of additional phenotypic mutations.
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Affiliation(s)
- Dušan Petrović
- Department of Chemistry, BMC, Uppsala University, Box 576, 751 23 Uppsala, Sweden
| | - Valeria A Risso
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain
| | | | - Jose M Sanchez-Ruiz
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain
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78
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Trade-offs with stability modulate innate and mutationally acquired drug resistance in bacterial dihydrofolate reductase enzymes. Biochem J 2018; 475:2107-2125. [PMID: 29871875 DOI: 10.1042/bcj20180249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 01/30/2023]
Abstract
Structural stability is a major constraint on the evolution of protein sequences. However, under strong directional selection, mutations that confer novel phenotypes but compromise structural stability of proteins may be permissible. During the evolution of antibiotic resistance, mutations that confer drug resistance often have pleiotropic effects on the structure and function of antibiotic-target proteins, usually essential metabolic enzymes. In the present study, we show that trimethoprim (TMP)-resistant alleles of dihydrofolate reductase from Escherichia coli (EcDHFR) harboring the Trp30Gly, Trp30Arg or Trp30Cys mutations are significantly less stable than the wild-type, making them prone to aggregation and proteolysis. This destabilization is associated with a lower expression level, resulting in a fitness cost and negative epistasis with other TMP-resistant mutations in EcDHFR. Using structure-based mutational analysis, we show that perturbation of critical stabilizing hydrophobic interactions in wild-type EcDHFR enzyme explains the phenotypes of Trp30 mutants. Surprisingly, though crucial for the stability of EcDHFR, significant sequence variation is found at this site among bacterial dihydrofolate reductases (DHFRs). Mutational and computational analyses in EcDHFR and in DHFR enzymes from Staphylococcus aureus and Mycobacterium tuberculosis demonstrate that natural variation at this site and its interacting hydrophobic residues modulates TMP resistance in other bacterial DHFRs as well, and may explain the different susceptibilities of bacterial pathogens to TMP. Our study demonstrates that trade-offs between structural stability and function can influence innate drug resistance as well as the potential for mutationally acquired drug resistance of an enzyme.
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79
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Risso VA, Sanchez-Ruiz JM, Ozkan SB. Biotechnological and protein-engineering implications of ancestral protein resurrection. Curr Opin Struct Biol 2018; 51:106-115. [PMID: 29660672 DOI: 10.1016/j.sbi.2018.02.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Revised: 02/18/2018] [Accepted: 02/20/2018] [Indexed: 10/17/2022]
Abstract
Approximations to the sequences of ancestral proteins can be derived from the sequences of their modern descendants. Proteins encoded by such reconstructed sequences can be prepared in the laboratory and subjected to experimental scrutiny. These 'resurrected' ancestral proteins often display remarkable properties, reflecting ancestral adaptations to intra-cellular and extra-cellular environments that differed from the environments hosting modern/extant proteins. Recent experimental and computational work has specifically discussed high stability, substrate and catalytic promiscuity, conformational flexibility/diversity and altered patterns of interaction with other sub-cellular components. In this review, we discuss these remarkable properties as well as recent attempts to explore their biotechnological and protein-engineering potential.
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Affiliation(s)
- Valeria A Risso
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain
| | - Jose M Sanchez-Ruiz
- Departamento de Quimica Fisica, Facultad de Ciencias, University of Granada, 18071 Granada, Spain.
| | - S Banu Ozkan
- Department of Physics and Center for Biological Physics, Arizona State University, Tempe, AZ 85281, United States.
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80
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Folate biosynthesis pathway: mechanisms and insights into drug design for infectious diseases. Future Med Chem 2018; 10:935-959. [PMID: 29629843 DOI: 10.4155/fmc-2017-0168] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Folate pathway is a key target for the development of new drugs against infectious diseases since the discovery of sulfa drugs and trimethoprim. The knowledge about this pathway has increased in the last years and the catalytic mechanism and structures of all enzymes of the pathway are fairly understood. In addition, differences among enzymes from prokaryotes and eukaryotes could be used for the design of specific inhibitors. In this review, we show a panorama of progress that has been achieved within the folate pathway obtained in the last years. We explored the structure and mechanism of enzymes, several genetic features, strategies, and approaches used in the design of new inhibitors that have been used as targets in pathogen chemotherapy.
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81
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Chen X, Schwartz SD. Directed Evolution as a Probe of Rate Promoting Vibrations Introduced via Mutational Change. Biochemistry 2018; 57:3289-3298. [PMID: 29553716 DOI: 10.1021/acs.biochem.8b00185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this article, we study with transition path sampling and reaction coordinate analysis how directed evolution in the Kemp eliminase family of artificial enzymes makes differential use of rapid rate promoting vibrations as a component of their chemical mechanism. Even though this family was initially created by placing the expected active site in a fixed protein matrix, we find a shift from largely static to more dynamic active sites that make use of donor-acceptor compression as the evolutionary process proceeds. We see that this introduction of dynamics significantly shifts the order of processes in the reaction. We also suggest that the lack of "design for dynamics" may help explain the relatively low proficiency of such designed enzymes.
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Affiliation(s)
- Xi Chen
- Department of Chemistry and Biochemistry , University of Arizona , 1306 East University Boulevard , Tucson , Arizona 85721 , United States
| | - Steven D Schwartz
- Department of Chemistry and Biochemistry , University of Arizona , 1306 East University Boulevard , Tucson , Arizona 85721 , United States
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82
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Boehr DD, D'Amico RN, O'Rourke KF. Engineered control of enzyme structural dynamics and function. Protein Sci 2018; 27:825-838. [PMID: 29380452 DOI: 10.1002/pro.3379] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 01/20/2018] [Accepted: 01/24/2018] [Indexed: 12/20/2022]
Abstract
Enzymes undergo a range of internal motions from local, active site fluctuations to large-scale, global conformational changes. These motions are often important for enzyme function, including in ligand binding and dissociation and even preparing the active site for chemical catalysis. Protein engineering efforts have been directed towards manipulating enzyme structural dynamics and conformational changes, including targeting specific amino acid interactions and creation of chimeric enzymes with new regulatory functions. Post-translational covalent modification can provide an additional level of enzyme control. These studies have not only provided insights into the functional role of protein motions, but they offer opportunities to create stimulus-responsive enzymes. These enzymes can be engineered to respond to a number of external stimuli, including light, pH, and the presence of novel allosteric modulators. Altogether, the ability to engineer and control enzyme structural dynamics can provide new tools for biotechnology and medicine.
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Affiliation(s)
- David D Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Rebecca N D'Amico
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
| | - Kathleen F O'Rourke
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania, 16802, USA
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83
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Vu PJ, Yao XQ, Momin M, Hamelberg D. Unraveling Allosteric Mechanisms of Enzymatic Catalysis with an Evolutionary Analysis of Residue–Residue Contact Dynamical Changes. ACS Catal 2018. [DOI: 10.1021/acscatal.7b04263] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Phuoc Jake Vu
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303-2515, United States
| | - Xin-Qiu Yao
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303-2515, United States
| | - Mohamed Momin
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303-2515, United States
| | - Donald Hamelberg
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303-2515, United States
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84
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Structural heterogeneity and dynamics in protein evolution and design. Curr Opin Struct Biol 2018; 48:157-163. [DOI: 10.1016/j.sbi.2018.01.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Accepted: 01/18/2018] [Indexed: 12/16/2022]
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85
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Cooperativity and flexibility in enzyme evolution. Curr Opin Struct Biol 2018; 48:83-92. [DOI: 10.1016/j.sbi.2017.10.020] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/24/2017] [Indexed: 11/23/2022]
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86
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Arai M. Unified understanding of folding and binding mechanisms of globular and intrinsically disordered proteins. Biophys Rev 2018; 10:163-181. [PMID: 29307002 PMCID: PMC5899706 DOI: 10.1007/s12551-017-0346-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 11/13/2017] [Indexed: 12/18/2022] Open
Abstract
Extensive experimental and theoretical studies have advanced our understanding of the mechanisms of folding and binding of globular proteins, and coupled folding and binding of intrinsically disordered proteins (IDPs). The forces responsible for conformational changes and binding are common in both proteins; however, these mechanisms have been separately discussed. Here, we attempt to integrate the mechanisms of coupled folding and binding of IDPs, folding of small and multi-subdomain proteins, folding of multimeric proteins, and ligand binding of globular proteins in terms of conformational selection and induced-fit mechanisms as well as the nucleation–condensation mechanism that is intermediate between them. Accumulating evidence has shown that both the rate of conformational change and apparent rate of binding between interacting elements can determine reaction mechanisms. Coupled folding and binding of IDPs occurs mainly by induced-fit because of the slow folding in the free form, while ligand binding of globular proteins occurs mainly by conformational selection because of rapid conformational change. Protein folding can be regarded as the binding of intramolecular segments accompanied by secondary structure formation. Multi-subdomain proteins fold mainly by the induced-fit (hydrophobic collapse) mechanism, as the connection of interacting segments enhances the binding (compaction) rate. Fewer hydrophobic residues in small proteins reduce the intramolecular binding rate, resulting in the nucleation–condensation mechanism. Thus, the folding and binding of globular proteins and IDPs obey the same general principle, suggesting that the coarse-grained, statistical mechanical model of protein folding is promising for a unified theoretical description of all mechanisms.
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Affiliation(s)
- Munehito Arai
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, 3-8-1 Komaba, Meguro, Tokyo, 153-8902, Japan.
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87
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Zinovjev K, Tuñón I. Quantifying the limits of transition state theory in enzymatic catalysis. Proc Natl Acad Sci U S A 2017; 114:12390-12395. [PMID: 29101125 PMCID: PMC5703300 DOI: 10.1073/pnas.1710820114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
While being one of the most popular reaction rate theories, the applicability of transition state theory to the study of enzymatic reactions has been often challenged. The complex dynamic nature of the protein environment raised the question about the validity of the nonrecrossing hypothesis, a cornerstone in this theory. We present a computational strategy to quantify the error associated to transition state theory from the number of recrossings observed at the equicommittor, which is the best possible dividing surface. Application of a direct multidimensional transition state optimization to the hydride transfer step in human dihydrofolate reductase shows that both the participation of the protein degrees of freedom in the reaction coordinate and the error associated to the nonrecrossing hypothesis are small. Thus, the use of transition state theory, even with simplified reaction coordinates, provides a good theoretical framework for the study of enzymatic catalysis.
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Affiliation(s)
- Kirill Zinovjev
- Departament de Química Física, Universitat de València, 46100 Burjassot, Spain
| | - Iñaki Tuñón
- Departament de Química Física, Universitat de València, 46100 Burjassot, Spain
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88
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Sun X, Dyson HJ, Wright PE. Fluorotryptophan Incorporation Modulates the Structure and Stability of Transthyretin in a Site-Specific Manner. Biochemistry 2017; 56:5570-5581. [PMID: 28920433 DOI: 10.1021/acs.biochem.7b00815] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Abnormal deposition of aggregated wild-type (WT) human transthyretin (TTR) and its pathogenic variants is responsible for cardiomyopathy and neuropathy related to TTR amyloidosis. The tryptophan (Trp) fluorescence measurements typically used to study structural changes of TTR do not yield site-specific information on the two Trp residues per TTR protomer. To obtain such information, tryptophan labeled with fluorine at the 5 and 6 positions (5FW and 6FW) was incorporated into TTR. Fluorescence of 5FW and 6FW-labeled WT-TTR (WT-5FW and WT-6FW) and a single-Trp mutant W41Y showed that the photophysics of incorporated fluoro-Trp is consistent with site-specific solvation of the indole ring of W41 and W79. 19F-NMR showed that solvent accessibility depends on both the location of the Trp and the position of the fluorine substituent in the indole ring. Unexpectedly, differences were observed in the rates of aggregation, with WT-6FW aggregating more rapidly than WT-5FW or WT-TTR. Real-time 19F-NMR urea unfolding experiments revealed that WT-5FW is kinetically more stable than WT-6FW, consistent with the aggregation assay. In addition, structural perturbations of residues distant from either Trp site are more extensive in WT-6FW. Notably, residues in the dimer interfaces are perturbed by 6FW at residue 79; pathogenic mutations in these regions are associated with reduced tetramer stability and amyloidogenesis. The differences in behavior that arise from the replacement of a fluorine at the 5-position of a tryptophan with one at the adjacent 6-position emphasize the delicate balance of stability in the TTR tetramer.
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Affiliation(s)
- Xun Sun
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - H Jane Dyson
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Peter E Wright
- Department of Integrative Structural and Computational Biology and Skaggs Institute of Chemical Biology, The Scripps Research Institute , 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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89
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Wachter RM. Photoconvertible Fluorescent Proteins and the Role of Dynamics in Protein Evolution. Int J Mol Sci 2017; 18:ijms18081792. [PMID: 32962314 PMCID: PMC5578180 DOI: 10.3390/ijms18081792] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 08/11/2017] [Accepted: 08/17/2017] [Indexed: 12/12/2022] Open
Abstract
Photoconvertible fluorescent proteins (pcFPs) constitute a large group of fluorescent proteins related to green fluorescent protein (GFP) that, when exposed to blue light, bear the capability of irreversibly switching their emission color from green to red. Not surprisingly, this fascinating class of FPs has found numerous applications, in particular for the visualization of biological processes. A detailed understanding of the photoconversion mechanism appears indispensable in the design of improved variants for applications such as super-resolution imaging. In this article, recent work is reviewed that involves using pcFPs as a model system for studying protein dynamics. Evidence has been provided that the evolution of pcFPs from a green ancestor involved the natural selection for altered dynamical features of the beta-barrel fold. It appears that photoconversion may be the outcome of a long-range positional shift of a fold-anchoring region. A relatively stiff, rigid element appears to have migrated away from the chromophore-bearing section to the opposite edge of the barrel, thereby endowing pcFPs with increased active site flexibility while keeping the fold intact. In this way, the stage was set for the coupling of light absorption with subsequent chemical transformations. The emerging mechanistic model suggests that highly specific dynamic motions are linked to key chemical steps, preparing the system for a concerted deprotonation and β-elimination reaction that enlarges the chromophore's π-conjugation to generate red color.
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Affiliation(s)
- Rebekka M Wachter
- School of Molecular Sciences and Center for Bioenergy and Photosynthesis, Arizona State University, Tempe, AZ 85287, USA
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90
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Kosciolek T, Buchan DWA, Jones DT. Predictions of Backbone Dynamics in Intrinsically Disordered Proteins Using De Novo Fragment-Based Protein Structure Predictions. Sci Rep 2017; 7:6999. [PMID: 28765603 PMCID: PMC5539115 DOI: 10.1038/s41598-017-07156-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 06/23/2017] [Indexed: 11/08/2022] Open
Abstract
Intrinsically disordaered proteins (IDPs) are a prevalent phenomenon with over 30% of human proteins estimated to have long disordered regions. Computational methods are widely used to study IDPs, however, nearly all treat disorder in a binary fashion, not accounting for the structural heterogeneity present in disordered regions. Here, we present a new de novo method, FRAGFOLD-IDP, which addresses this problem. Using 200 protein structural ensembles derived from NMR, we show that FRAGFOLD-IDP achieves superior results compared to methods which can predict related data (NMR order parameter, or crystallographic B-factor). FRAGFOLD-IDP produces very good predictions for 33.5% of cases and helps to get a better insight into the dynamics of the disordered ensembles. The results also show it is not necessary to predict the correct fold of the protein to reliably predict per-residue fluctuations. It implies that disorder is a local property and it does not depend on the fold. Our results are orthogonal to DynaMine, the only other method significantly better than the naïve prediction. We therefore combine these two using a neural network. FRAGFOLD-IDP enables better insight into backbone dynamics in IDPs and opens exciting possibilities for the design of disordered ensembles, disorder-to-order transitions, or design for protein dynamics.
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Affiliation(s)
- Tomasz Kosciolek
- Bioinformatics Group, Department of Computer Science, University College London, Gower Street, London, WC1E 6BT, United Kingdom
- Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA
| | - Daniel W A Buchan
- Bioinformatics Group, Department of Computer Science, University College London, Gower Street, London, WC1E 6BT, United Kingdom
| | - David T Jones
- Bioinformatics Group, Department of Computer Science, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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91
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Vieira GC, Vieira GF, Sinigaglia M, da Silva Valente VL. Linking epigenetic function to electrostatics: The DNMT2 structural model example. PLoS One 2017; 12:e0178643. [PMID: 28575027 PMCID: PMC5456315 DOI: 10.1371/journal.pone.0178643] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/16/2017] [Indexed: 11/25/2022] Open
Abstract
The amino acid sequence of DNMT2 is very similar to the catalytic domains of bacterial and eukaryotic proteins. However, there is great variability in the region of recognition of the target sequence. While bacterial DNMT2 acts as a DNA methyltransferase, previous studies have indicated low DNA methylation activity in eukaryotic DNMT2, with preference by tRNA methylation. Drosophilids are known as DNMT2-only species and the DNA methylation phenomenon is a not elucidated case yet, as well as the ontogenetic and physiologic importance of DNMT2 for this species group. In addition, more recently study showed that methylation in the genome in Drosophila melanogaster is independent in relation to DNMT2. Despite these findings, Drosophilidae family has more than 4,200 species with great ecological diversity and historical evolution, thus we, therefore, aimed to examine the drosophilids DNMT2 in order to verify its conservation at the physicochemical and structural levels in a functional context. We examined the twenty-six DNMT2 models generated by molecular modelling and five crystallographic structures deposited in the Protein Data Bank (PDB) using different approaches. Our results showed that despite sequence and structural similarity between species close related, we found outstanding differences when they are analyzed in the context of surface distribution of electrostatic properties. The differences found in the electrostatic potentials may be linked with different affinities and processivity of DNMT2 for its different substrates (DNA, RNA or tRNA) and even for interactions with other proteins involved in the epigenetic mechanisms.
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Affiliation(s)
- Gilberto Cavalheiro Vieira
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- * E-mail:
| | - Gustavo Fioravanti Vieira
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Núcleo de Bioinformática do Laboratório de Imunogenética, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Marialva Sinigaglia
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Instituto do Câncer Infantil, Porto Alegre, RS, Brazil
| | - Vera Lúcia da Silva Valente
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
- Programa de Pós Graduação em Biologia Animal, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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92
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Serrão VHB, Romanello L, Cassago A, de Souza JRT, Cheleski J, DeMarco R, Brandão-Neto J, Pereira HD. Structure and kinetics assays of recombinant Schistosoma mansoni dihydrofolate reductase. Acta Trop 2017; 170:190-196. [PMID: 28288799 DOI: 10.1016/j.actatropica.2017.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 10/20/2022]
Abstract
The parasite Schistosoma mansoni possesses all pathways for pyrimidine biosynthesis, in which dihydrofolate reductase (DHFR), thymidylate cycle participants, is essential for nucleotide metabolism to obtain energy and structural nucleic acids. Thus, DHFRs have been widely suggested as therapeutic targets for the treatment of infectious diseases. In this study, we expressed recombinant SmDHFR in a heterologous manner to obtain structural, biochemical and kinetic information. X-ray diffraction of recombinant SmDHFR at 1.95Å resolution showed that the structure exhibited the canonical DHFR fold. Isothermal titration calorimetry was used to determine the kinetic constants for NADP+ and dihydrofolate. Moreover, inhibition assays were performed using the commercial folate analogs methotrexate and aminopterin; these analogs are recognized as folate competitors and are used as chemotherapeutic agents in cancer and autoimmune diseases. This study provides information that may prove useful for the future discovery of novel drugs and for understanding these metabolic steps from this pathway of S. mansoni, thus aiding in our understanding of the function of these essential pathways for parasite metabolism.
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93
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Toulouse JL, Abraham SMJ, Kadnikova N, Bastien D, Gauchot V, Schmitzer AR, Pelletier JN. Investigation of Classical Organic and Ionic Liquid Cosolvents for Early-Stage Screening in Fragment-Based Inhibitor Design with Unrelated Bacterial and Human Dihydrofolate Reductases. Assay Drug Dev Technol 2017; 15:141-153. [PMID: 28426233 DOI: 10.1089/adt.2016.768] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drug design by methods such as fragment screening requires effective solubilization of millimolar concentrations of small organic compounds while maintaining the properties of the biological target. We investigate four organic solvents and three 1-butyl-3-methylimidazolium (BMIm)-based ionic liquids (ILs) as cosolvents to establish conditions for screening two structurally unrelated dihydrofolate reductases (DHFRs) that are prime drug targets. Moderate concentrations (10%-15%) of cosolvents had little effect on inhibition of the microbial type II R67 DHFR and of human DHFR (hDHFR), while higher concentrations of organic cosolvents generally decreased activity of both DHFRs. In contrast, a specific IL conserved the activity of one DHFR, while severely reducing the activity of the other, and vice versa, illustrating the differing effect of ILs on distinct protein folds. Most of the cosolvents investigated preserved the fold of R67 DHFR and had little effect on binding of the cofactor NADPH, but reduced the productive affinity for its substrate. In contrast, cosolvents resulted in modest structural destabilization of hDHFR with little effect on productive affinity. We conclude that the organic cosolvents, methanol, dimethylformamide, and dimethylsulfoxide, offer the most balanced conditions for early-stage compound screening as they maintain sufficient biological activity of both DHFRs while allowing for compound dissolution in the millimolar range. However, IL cosolvents showed poor capacity to solubilize organic compounds at millimolar concentrations, mitigating their utility in early-stage screening. Nonetheless, ILs could provide an alternative to classical organic cosolvents when low concentrations of inhibitors are used, as when characterizing higher affinity inhibitors.
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Affiliation(s)
- Jacynthe L Toulouse
- 1 Département de Biochimie, Université de Montréal , Québec, Canada .,2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,3 PROTEO , The Québec Network for Protein Function, Structure and Engineering, Québec, Canada
| | - Sarah M J Abraham
- 2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,3 PROTEO , The Québec Network for Protein Function, Structure and Engineering, Québec, Canada .,4 Département de Chimie, Université de Montréal , Québec, Canada
| | - Natalia Kadnikova
- 2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,3 PROTEO , The Québec Network for Protein Function, Structure and Engineering, Québec, Canada .,4 Département de Chimie, Université de Montréal , Québec, Canada
| | - Dominic Bastien
- 1 Département de Biochimie, Université de Montréal , Québec, Canada .,2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,3 PROTEO , The Québec Network for Protein Function, Structure and Engineering, Québec, Canada
| | - Vincent Gauchot
- 2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,4 Département de Chimie, Université de Montréal , Québec, Canada
| | - Andreea R Schmitzer
- 2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,4 Département de Chimie, Université de Montréal , Québec, Canada
| | - Joelle N Pelletier
- 1 Département de Biochimie, Université de Montréal , Québec, Canada .,2 CGCC, The Center in Green Chemistry and Catalysis , Montréal, Québec, Canada .,3 PROTEO , The Québec Network for Protein Function, Structure and Engineering, Québec, Canada .,4 Département de Chimie, Université de Montréal , Québec, Canada
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94
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Hughes RL, Johnson LA, Behiry EM, Loveridge EJ, Allemann RK. A Rapid Analysis of Variations in Conformational Behavior during Dihydrofolate Reductase Catalysis. Biochemistry 2017; 56:2126-2133. [PMID: 28368101 DOI: 10.1021/acs.biochem.7b00045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Protein flexibility is central to enzyme catalysis, yet it remains challenging both to predict conformational behavior on the basis of analysis of amino acid sequence and protein structure and to provide the necessary breadth of experimental support to any such predictions. Here a generic and rapid procedure for identifying conformational changes during dihydrofolate reductase (DHFR) catalysis is described. Using DHFR from Escherichia coli (EcDHFR), selective side-chain 13C labeling of methionine and tryptophan residues is shown to be sufficient to detect the closed-to-occluded conformational transition that follows the chemical step in the catalytic cycle, with clear chemical shift perturbations found for both methionine methyl and tryptophan indole groups. In contrast, no such perturbations are seen for the DHFR from the psychrophile Moritella profunda, where the equivalent conformational change is absent. Like EcDHFR, Salmonella enterica DHFR shows experimental evidence of a large-scale conformational change following hydride transfer that relies on conservation of a key hydrogen bonding interaction between the M20 and GH loops, directly comparable to the closed-to-occluded conformational change observed in EcDHFR. For the hyperthermophile Thermotoga maritima, no chemical shift perturbations were observed, suggesting that no major conformational change occurs during the catalytic cycle. In spite of their conserved tertiary structures, DHFRs display variations in conformational sampling that occurs concurrently with catalysis.
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Affiliation(s)
- Robert L Hughes
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Luke A Johnson
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Enas M Behiry
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - E Joel Loveridge
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
| | - Rudolf K Allemann
- School of Chemistry, Cardiff University , Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
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95
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Molecular Characteristics and Serodiagnostic Potential of Dihydrofolate Reductase from Echinococcus granulosus. Sci Rep 2017; 7:514. [PMID: 28364125 PMCID: PMC5428777 DOI: 10.1038/s41598-017-00643-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 03/07/2017] [Indexed: 02/02/2023] Open
Abstract
The larval stage of Echinococcus granulosus causes cystic echinococcosis (CE), a neglected tropical disease that leads to morbidity and mortality in humans and livestock worldwide. Here, we identified and characterized dihydrofolate reductase (Eg-DHFR) from E. granulosus, and evaluated its potential as a diagnostic antigen for sheep CE. Comparison between mammalian (host) DHFR and Eg-DHFR indicates that 45.7% of the 35 active site residues are different. Immunolocalisation analysis showed that native Eg-DHFR was widely distributed in all life-cycle stages of E. granulosus. Recombinant Eg-DHFR (rEg-DHFR) showed typical DHFR enzymatic parameters towards substrate, and was very sensitive to inhibition by methotrexate (IC50 = 27.75 ± 1.03 nM) and aminopterin (IC50 = 63.67 ± 6.76 nM). However, inhibition of DHFR exhibited little protoscolicidal effect in vitro. As there is no reliable method to monitor sheep CE, the immunogenicity of rEg-DHFR was detected, and we developed an indirect ELISA (iELISA) for CE serodiagnosis. The iELISA exhibited diagnostic specificity of 89.58%, diagnostic sensitivity of 95.83%, and the diagnostic accuracy was 91.67% compared with necropsy. Cross-reactivity assay showed analytical specificity of 85.7%. These suggest that rEg-DHFR is an effective antigen for the diagnosis of sheep CE.
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96
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Cammarata M, Thyer R, Lombardo M, Anderson A, Wright D, Ellington A, Brodbelt JS. Characterization of trimethoprim resistant E. coli dihydrofolate reductase mutants by mass spectrometry and inhibition by propargyl-linked antifolates. Chem Sci 2017; 8:4062-4072. [PMID: 29967675 PMCID: PMC6020862 DOI: 10.1039/c6sc05235e] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 03/24/2017] [Indexed: 12/12/2022] Open
Abstract
Native mass spectrometry, size exclusion chromatography, and kinetic assays were employed to study trimethoprim resistance in E. coli caused by mutations P21L and W30R of dihydrofolate reductase.
Pathogenic Escherichia coli, one of the primary causes of urinary tract infections, has shown significant resistance to the most popular antibiotic, trimethoprim (TMP), which inhibits dihydrofolate reductase (DHFR). The resistance is modulated by single point mutations of DHFR. The impact of two clinically relevant mutations, P21L and W30R, on the activity of DHFR was evaluated via measurement of Michaelis–Menten and inhibitory kinetics, and structural characterization was undertaken by native mass spectrometry with ultraviolet photodissociation (UVPD). Compared to WT-DHFR, both P21L and W30R mutants produced less stable complexes with TMP in the presence of co-factor NADPH as evidenced by the relative abundances of complexes observed in ESI mass spectra. Moreover, based on variations in the fragmentation patterns obtained by UVPD mass spectrometry of binary and ternary DHFR complexes, notable structural changes were localized to the substrate binding pocket for W30R and to the M20 loop region as well as the C-terminal portion containing the essential G–H functional loop for the P21L mutant. The results suggest that the mutations confer resistance through distinctive mechanisms. A novel propargyl-linked antifolate compound 1038 was shown to be a reasonably effective inhibitor of the P21L mutant.
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Affiliation(s)
- Michael Cammarata
- Department of Chemistry , University of Texas , Austin , TX 78712 , USA .
| | - Ross Thyer
- Center for Systems and Synthetic Biology , University of Texas , Austin , TX 78712 , USA
| | - Michael Lombardo
- Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT 06269 , USA
| | - Amy Anderson
- Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT 06269 , USA
| | - Dennis Wright
- Department of Pharmaceutical Sciences , University of Connecticut , Storrs , CT 06269 , USA
| | - Andrew Ellington
- Center for Systems and Synthetic Biology , University of Texas , Austin , TX 78712 , USA
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97
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Maggi F, Papa F, Pucciarelli S, Bramucci M, Quassinti L, Barboni L, Ben DD, Ramadori AT, Graiff C, Galassi R. Stabilization of the cyclodecadiene derivative isofuranodiene by silver (I) coordination. Mechanistic and biological aspects. Fitoterapia 2017; 117:52-60. [PMID: 28069487 DOI: 10.1016/j.fitote.2016.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/11/2016] [Accepted: 12/18/2016] [Indexed: 10/20/2022]
Abstract
The industrial extraction and further applications of isofuranodiene are limited because at room temperature it spontaneously converts to curzerene, a structurally less active isomer. This work definitively identified the structure of isofuranodiene in the solid state, showing the two methyl groups in syn position. In addition, two bioactive metal cations, namely, silver(I) and copper(II) ions, were used in the attempt to obtain the chemical stability of isofuranodiene: in the case of silver(I), a labile adduct was formed, while in the case of copper(II), a more stable 1:1 adduct was achieved. In the former, the presence of silver did not significantly affect the biological activities of isofuranodiene, while in the latter, the copper(II) coordination suppressed them. The biological activities of the isofuranodiene adducts were then evaluated as antiproliferative agents against human tumor cell lines (HCT116, MDA-MB 231, and T98G). In addition, for the first time, isofuranodiene was tested as an inhibitor of DHFR (DiHydroFolateReductase) from Escherichia coli. Anticancer activity was observed in the isofuranodiene with the AgCF3SO3 adduct, in the tested cell lines, with IC50 values ranging from 4.89μM to 13.06μM, while inhibition assays highlighted a Ki of 6.22μM for isofuranodiene and of 0.17μM for the related silver adduct. Docking studies indicated a binding mode score of -6.83Kcal/mol for isofuranodiene, and an energy value of -11.82Kcal/mol for methotrexate (a classic DHFR inhibitor).
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Affiliation(s)
- Filippo Maggi
- School of Pharmacy, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Fabrizio Papa
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Stefania Pucciarelli
- School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, I-62032 Camerino, Italy
| | - Massimo Bramucci
- School of Pharmacy, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Luana Quassinti
- School of Pharmacy, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Luciano Barboni
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Diego Dal Ben
- School of Pharmacy, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Anna Teresa Ramadori
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy
| | - Claudia Graiff
- Dipartimento di Chimica, Università di Parma, Viale delle Scienze 17/A, 43100 Parma, Italy
| | - Rossana Galassi
- School of Science and Technology, Chemistry Division, University of Camerino, Via S. Agostino, 1, I-62032 Camerino, Italy.
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98
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Alotaibi M, Reyes BD, Le T, Luong P, Valafar F, Metzger RP, Fogel GB, Hecht D. Structure-based analysis of Bacilli and plasmid dihydrofolate reductase evolution. J Mol Graph Model 2017; 71:135-153. [PMID: 27914300 PMCID: PMC5203806 DOI: 10.1016/j.jmgm.2016.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 10/04/2016] [Accepted: 10/10/2016] [Indexed: 12/15/2022]
Abstract
Dihydrofolate reductase (DHFR), a key enzyme in tetrahydrofolate-mediated biosynthetic pathways, has a structural motif known to be highly conserved over a wide range of organisms. Given its critical role in purine and amino acid synthesis, DHFR is a well established therapeutic target for treating a wide range of prokaryotic and eukaryotic infections as well as certain types of cancer. Here we present a structural-based computer analysis of bacterial (Bacilli) and plasmid DHFR evolution. We generated a structure-based sequence alignment using 7 wild-type DHFR x-ray crystal structures obtained from the RCSB Protein Data Bank and 350 chromosomal and plasmid homology models we generated from sequences obtained from the NCBI Protein Database. We used these alignments to compare active site and non-active site conservation in terms of amino acid residues, secondary structure and amino acid residue class. With respect to amino acid sequences and residue classes, active-site positions in both plasmid and chromosomal DHFR are significantly more conserved than non-active site positions. Secondary structure conservation was similar for active site and non-active site positions. Plasmid-encoded DHFR proteins have greater degree of sequence and residue class conservation, particularly in sequence positions associated with a network of concerted protein motions, than chromosomal-encoded DHFR proteins. These structure-based were used to build DHFR specific phylogenetic trees from which evidence for horizontal gene transfer was identified.
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Affiliation(s)
- Mona Alotaibi
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA; King Saud University, P.O. Box 245714, Riyadh 11312, Saudi Arabia.
| | - Ben Delos Reyes
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA
| | - Tin Le
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA
| | - Phuong Luong
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA
| | - Faramarz Valafar
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego, CA 92182-7720, USA.
| | - Robert P Metzger
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA.
| | - Gary B Fogel
- Natural Selection, Inc., 6480 Weathers Place, Suite 350, San Diego, CA 92121, USA.
| | - David Hecht
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030, USA; Department of Chemistry, Southwestern College, 900 Otay Lakes Rd., Chula Vista, CA 91910, USA.
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99
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Liu W, Huang B, Kuang Y, Liu G. Molecular dynamics simulations elucidate conformational selection and induced fit mechanisms in the binding of PD-1 and PD-L1. MOLECULAR BIOSYSTEMS 2017; 13:892-900. [DOI: 10.1039/c7mb00036g] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PD-L1 binds PD-1 through a complex mechanism including both the conformational selection and induced fit pathways.
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Affiliation(s)
- Wenping Liu
- School of Bioscience and Bioengineering
- South China University of Technology
- Guangzhou 510006
- China
- Division of Birth Cohort Study
| | - Bing Huang
- School of Bioscience and Bioengineering
- South China University of Technology
- Guangzhou 510006
- China
| | - Yashu Kuang
- Division of Birth Cohort Study
- Guangzhou Women and Children's Medical Center
- Guangzhou Medical University
- Guangzhou 510623
- China
| | - Guangjian Liu
- Division of Birth Cohort Study
- Guangzhou Women and Children's Medical Center
- Guangzhou Medical University
- Guangzhou 510623
- China
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100
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Genome-wide mapping of mutations at single-nucleotide resolution for protein, metabolic and genome engineering. Nat Biotechnol 2016; 35:48-55. [PMID: 27941803 DOI: 10.1038/nbt.3718] [Citation(s) in RCA: 242] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 10/05/2016] [Indexed: 01/20/2023]
Abstract
Improvements in DNA synthesis and sequencing have underpinned comprehensive assessment of gene function in bacteria and eukaryotes. Genome-wide analyses require high-throughput methods to generate mutations and analyze their phenotypes, but approaches to date have been unable to efficiently link the effects of mutations in coding regions or promoter elements in a highly parallel fashion. We report that CRISPR-Cas9 gene editing in combination with massively parallel oligomer synthesis can enable trackable editing on a genome-wide scale. Our method, CRISPR-enabled trackable genome engineering (CREATE), links each guide RNA to homologous repair cassettes that both edit loci and function as barcodes to track genotype-phenotype relationships. We apply CREATE to site saturation mutagenesis for protein engineering, reconstruction of adaptive laboratory evolution experiments, and identification of stress tolerance and antibiotic resistance genes in bacteria. We provide preliminary evidence that CREATE will work in yeast. We also provide a webtool to design multiplex CREATE libraries.
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