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Chen Y, Sewsurn S, Amand S, Kunz C, Pietrancosta N, Calabro K, Buisson D, Mann S. Metabolic Investigation and Auxiliary Enzyme Modelization of the Pyrrocidine Pathway Allow Rationalization of Paracyclophane-Decahydrofluorene Formation. ACS Chem Biol 2024; 19:886-895. [PMID: 38576157 DOI: 10.1021/acschembio.3c00684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Fungal paracyclophane-decahydrofluorene-containing natural products are complex polycyclic metabolites derived from similar hybrid PKS-NRPS pathways. Herein we studied the biosynthesis of pyrrocidines, one representative of this family, by gene inactivation in the producer Sarocladium zeae coupled to thorough metabolic analysis and molecular modeling of key enzymes. We characterized nine pyrrocidines and analogues as well as in mutants a variety of accumulating metabolites with new structures including rare cis-decalin, cytochalasan, and fused 6/15/5 macrocycles. This diversity highlights the extraordinary plasticity of the pyrrocidine biosynthetic gene cluster. From accumulating metabolites, we delineated the scenario of pyrrocidine biosynthesis. The ring A of the decahydrofluorene is installed by PrcB, a membrane-bound cyclizing isomerase, on a PKS-NRPS-derived pyrrolidone precursor. Docking experiments in PrcB allowed us to characterize the active site suggesting a mechanism triggered by arginine-mediated deprotonation at the terminal methyl of the substrate. Next, two integral membrane proteins, PrcD and PrcE, each predicted as a four-helix bundle, perform hydroxylation of the pyrrolidone ring and paracyclophane formation, respectively. Modelization of PrcE highlights a topological homology with vitamin K oxido-reductase and the presence of a disulfide bond. Our results suggest a previously unsuspected coupling mechanism via a transient loss of aromaticity of tyrosine residue to form the strained paracyclophane motif. Finally, the lipocalin-like protein PrcX drives the exo-cycloaddition yielding ring B and C of the decahydrofluorene to afford pyrrocidine A, which is transformed by a reductase PrcI to form pyrrocidine B. These insights will greatly facilitate the microbial production of pyrrocidine analogues by synthetic biology.
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Affiliation(s)
- Youwei Chen
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
| | - Steffi Sewsurn
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
| | - Séverine Amand
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
| | - Caroline Kunz
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
- Sorbonne Université, Faculté des Sciences et Ingénierie, UFR 927, F-75005 Paris, France
| | - Nicolas Pietrancosta
- Laboratoire des Biomolécules, LBM, Sorbonne Université, École Normale Supérieure, PSL University, CNRS, F-75005 Paris, France
- Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS), Sorbonne Université, INSERM, CNRS, F-75005 Paris, France
| | - Kevin Calabro
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
| | - Didier Buisson
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
| | - Stéphane Mann
- Laboratoire Molécules de Communication et Adaptation des Micro-organismes UMR 7245, Muséum National d'Histoire Naturelle, CNRS, Sorbonne Universités; CP54, 57 rue Cuvier, 75005 Paris, France
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2
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Guo X, Chen R, Cao L. Molecular docking-based virtual screening and dynamics simulation study of novel and potential SIRT7 inhibitors. Chem Biol Drug Des 2023; 102:707-717. [PMID: 37287091 DOI: 10.1111/cbdd.14277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/11/2023] [Accepted: 05/22/2023] [Indexed: 06/09/2023]
Abstract
In cancer cells, short for sirtuin (SIRT7) stabilizes the transformed state via its nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase activity. Epigenetic factor SIRT7 plays important roles in cancer biology, reversing cancer phenotypes and suppressing tumor growth when inactive. In the present study, we got the SIRT7 protein structure from Alpha Fold2 Database and performed structure-based virtual screening to develop specific SIRT7 inhibitors using the SIRT7 inhibitor 97,491 interaction mechanism. As candidates for specific SIRT7 inhibitors, compounds with high affinities to SIRT7 were chosen. ZINC000001910616 and ZINC000014708529, two of our leading compounds, showed strong interactions with SIRT7. Our MD simulation results also revealed that the 5-hydroxy-4H-thioxen-4-one group and terminal carboxyl group were critical groups responsible for interaction of small molecules with SIRT7. In our study, we demonstrated that targeting SIRT7 may offer novel therapeutic options for cancer treatment. Compounds ZINC000001910616 and ZINC000014708529 can serve as chemical probes to investigate SIRT7 biological functions and provide starting points for the development of novel therapeutics against cancers.
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Affiliation(s)
- Xinli Guo
- Department of Operating Room, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Rui Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Liping Cao
- Department of General Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Zhejiang Engineering Research Center of Cognitive Healthcare, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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3
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Schultz SK, Kothe U. Fluorescent labeling of tRNA for rapid kinetic interaction studies with tRNA-binding proteins. Methods Enzymol 2023; 692:103-126. [PMID: 37925176 DOI: 10.1016/bs.mie.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2023]
Abstract
Transfer RNA (tRNA) plays a critical role during translation and interacts with numerous proteins during its biogenesis, functional cycle and degradation. In particular, tRNA is extensively post-transcriptionally modified by various tRNA modifying enzymes which each target a specific nucleotide at different positions within tRNAs to introduce different chemical modifications. Fluorescent assays can be used to study the interaction between a protein and tRNA. Moreover, rapid mixing fluorescence stopped-flow assays provide insights into the kinetics of the tRNA-protein interaction in order to elucidate the tRNA binding mechanism for the given protein. A prerequisite for these studies is a fluorescently labeled molecule, such as fluorescent tRNA, wherein a change in fluorescence occurs upon protein binding. In this chapter, we discuss the utilization of tRNA modifications in order to introduce fluorophores at particular positions within tRNAs. Particularly, we focus on in vitro thiolation of a uridine at position 8 within tRNAs using the tRNA modification enzyme ThiI, followed by labeling of the thiol group with fluorescein. As such, this fluorescently labeled tRNA is primarily unmodified, with the exception of the thiolation modification to which the fluorophore is attached, and can be used as a substrate to study the binding of different tRNA-interacting factors. Herein, we discuss the example of studying the tRNA binding mechanism of the tRNA modifying enzymes TrmB and DusA using internally fluorescein-labeled tRNA.
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Affiliation(s)
- Sarah K Schultz
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada; Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada
| | - Ute Kothe
- Alberta RNA Research and Training Institute (ARRTI), Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada; Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada.
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4
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Czekay DP, Kothe U. H/ACA Small Ribonucleoproteins: Structural and Functional Comparison Between Archaea and Eukaryotes. Front Microbiol 2021; 12:654370. [PMID: 33776984 PMCID: PMC7991803 DOI: 10.3389/fmicb.2021.654370] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 02/18/2021] [Indexed: 01/04/2023] Open
Abstract
During ribosome synthesis, ribosomal RNA is modified through the formation of many pseudouridines and methylations which contribute to ribosome function across all domains of life. In archaea and eukaryotes, pseudouridylation of rRNA is catalyzed by H/ACA small ribonucleoproteins (sRNPs) utilizing different H/ACA guide RNAs to identify target uridines for modification. H/ACA sRNPs are conserved in archaea and eukaryotes, as they share a common general architecture and function, but there are also several notable differences between archaeal and eukaryotic H/ACA sRNPs. Due to the higher protein stability in archaea, we have more information on the structure of archaeal H/ACA sRNPs compared to eukaryotic counterparts. However, based on the long history of yeast genetic and other cellular studies, the biological role of H/ACA sRNPs during ribosome biogenesis is better understood in eukaryotes than archaea. Therefore, this review provides an overview of the current knowledge on H/ACA sRNPs from archaea, in particular their structure and function, and relates it to our understanding of the roles of eukaryotic H/ACA sRNP during eukaryotic ribosome synthesis and beyond. Based on this comparison of our current insights into archaeal and eukaryotic H/ACA sRNPs, we discuss what role archaeal H/ACA sRNPs may play in the formation of ribosomes.
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Affiliation(s)
- Dominic P Czekay
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB, Canada
| | - Ute Kothe
- Department of Chemistry and Biochemistry, Alberta RNA Research and Training Institute, University of Lethbridge, Lethbridge, AB, Canada
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5
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Kurimoto R, Chiba T, Ito Y, Matsushima T, Yano Y, Miyata K, Yashiro Y, Suzuki T, Tomita K, Asahara H. The tRNA pseudouridine synthase TruB1 regulates the maturation of let-7 miRNA. EMBO J 2020; 39:e104708. [PMID: 32926445 PMCID: PMC7560213 DOI: 10.15252/embj.2020104708] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 08/07/2020] [Accepted: 08/08/2020] [Indexed: 12/14/2022] Open
Abstract
Let-7 is an evolutionary conserved microRNA that mediates post-transcriptional gene silencing to regulate a wide range of biological processes, including development, differentiation, and tumor suppression. Let-7 biogenesis is tightly regulated by several RNA-binding proteins, including Lin28A/B, which represses let-7 maturation. To identify new regulators of let-7, we devised a cell-based functional screen of RNA-binding proteins using a let-7 sensor luciferase reporter and identified the tRNA pseudouridine synthase, TruB1. TruB1 enhanced maturation specifically of let-7 family members. Rather than inducing pseudouridylation of the miRNAs, high-throughput sequencing crosslinking immunoprecipitation (HITS-CLIP) and biochemical analyses revealed direct binding between endogenous TruB1 and the stem-loop structure of pri-let-7, which also binds Lin28A/B. TruB1 selectively enhanced the interaction between pri-let-7 and the microprocessor DGCR8, which mediates miRNA maturation. Finally, TruB1 suppressed cell proliferation, which was mediated in part by let-7. Altogether, we reveal an unexpected function for TruB1 in promoting let-7 maturation.
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Affiliation(s)
- Ryota Kurimoto
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Tomoki Chiba
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Yoshiaki Ito
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
- Research CoreResearch Facility ClusterInstitute of ResearchTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Takahide Matsushima
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Yuki Yano
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
| | - Kohei Miyata
- Department Obstetrics and GynecologyFaculty of MedicineFukuoka UniversityFukuokaJapan
| | - Yuka Yashiro
- Department of Computational Biology and Medical SciencesGraduate School of Frontier SciencesThe University of TokyoKashiwaChibaJapan
| | - Tsutomu Suzuki
- Department of Chemistry and BiotechnologyGraduate School of EngineeringUniversity of TokyoTokyoJapan
| | - Kozo Tomita
- Department of Computational Biology and Medical SciencesGraduate School of Frontier SciencesThe University of TokyoKashiwaChibaJapan
| | - Hiroshi Asahara
- Department of Systems BioMedicineGraduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan
- Department of Molecular and Experimental MedicineThe Scripps Research InstituteSan DiegoCAUSA
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6
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Schultz SKL, Kothe U. tRNA elbow modifications affect the tRNA pseudouridine synthase TruB and the methyltransferase TrmA. RNA (NEW YORK, N.Y.) 2020; 26:1131-1142. [PMID: 32385137 PMCID: PMC7430675 DOI: 10.1261/rna.075473.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 05/04/2020] [Indexed: 05/20/2023]
Abstract
tRNAs constitute the most highly modified class of RNA. Every tRNA contains a unique set of modifications, and Ψ55, m5U54, and m7G46 are frequently found within the elbow of the tRNA structure. Despite the abundance of tRNA modifications, we are only beginning to understand the orchestration of modification enzymes during tRNA maturation. Here, we investigated whether pre-existing modifications impact the binding affinity or catalysis by tRNA elbow modification enzymes. Specifically, we focused on the Escherichia coli enzymes TruB, TrmA, and TrmB which generate Ψ55, m5U54, and m7G46, respectively. tRNAs containing a single modification were prepared, and the binding and activity preferences of purified E. coli TrmA, TruB, and TrmB were examined in vitro. TruB preferentially binds and modifies unmodified tRNA. TrmA prefers to modify unmodified tRNA, but binds most tightly to tRNA that already contains Ψ55. In contrast, binding and modification by TrmB is insensitive to the tRNA modification status. Our results suggest that TrmA and TruB are likely to act on mostly unmodified tRNA precursors during the early stages of tRNA maturation whereas TrmB presumably acts on later tRNA intermediates that are already partially modified. In conclusion, we uncover the mechanistic basis for the preferred modification order in the E. coli tRNA elbow region.
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Affiliation(s)
- Sarah Kai-Leigh Schultz
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
| | - Ute Kothe
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, Canada T1K 3M4
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7
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Karunanithy G, Reinstein J, Hansen DF. Multiquantum Chemical Exchange Saturation Transfer NMR to Quantify Symmetrical Exchange: Application to Rotational Dynamics of the Guanidinium Group in Arginine Side Chains. J Phys Chem Lett 2020; 11:5649-5654. [PMID: 32543198 PMCID: PMC7370295 DOI: 10.1021/acs.jpclett.0c01322] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Chemical exchange saturation transfer (CEST) NMR experiments have emerged as a powerful tool for characterizing dynamics in proteins. We show here that the CEST approach can be extended to systems with symmetrical exchange, where the NMR signals of all exchanging species are severely broadened. To achieve this, multiquantum CEST (MQ-CEST) is introduced, where the CEST pulse is applied to a longitudinal multispin order density element and the CEST profiles are encoded onto nonbroadened nuclei. The MQ-CEST approach is demonstrated on the restricted rotation of guanidinium groups in arginine residues within proteins. These groups and their dynamics are essential for many enzymes and for noncovalent interactions through the formation of hydrogen bonds, salt-bridges, and π-stacking interactions, and their rate of rotation is highly indicative of the extent of interactions formed. The MQ-CEST method is successfully applied to guanidinium groups in the 19 kDa L99A mutant of T4 lysozyme.
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Affiliation(s)
- Gogulan Karunanithy
- Institute
of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Jochen Reinstein
- Department
of Biomolecular Mechanisms, Max Planck Institute
for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany
| | - D. Flemming Hansen
- Institute
of Structural and Molecular Biology, Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
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8
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Kiss DJ, Oláh J, Tóth G, Menyhárd DK, Ferenczy GG. Quantum chemical calculations support pseudouridine synthase reaction through a glycal intermediate and provide details of the mechanism. Theor Chem Acc 2018. [DOI: 10.1007/s00214-018-2361-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Temburnikar K, Seley-Radtke KL. Recent advances in synthetic approaches for medicinal chemistry of C-nucleosides. Beilstein J Org Chem 2018; 14:772-785. [PMID: 29719574 PMCID: PMC5905277 DOI: 10.3762/bjoc.14.65] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/06/2018] [Indexed: 12/13/2022] Open
Abstract
C-nucleosides have intrigued biologists and medicinal chemists since their discovery in 1950's. In that regard, C-nucleosides and their synthetic analogues have resulted in promising leads in drug design. Concurrently, advances in chemical syntheses have contributed to structural diversity and drug discovery efforts. Convergent and modular approaches to synthesis have garnered much attention in this regard. Among them nucleophilic substitution at C1' has seen wide applications providing flexibility in synthesis, good yields, the ability to maneuver stereochemistry as well as to incorporate structural modifications. In this review, we describe recent reports on the modular synthesis of C-nucleosides with a focus on D-ribonolactone and sugar modifications that have resulted in potent lead molecules.
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Affiliation(s)
- Kartik Temburnikar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe St. Baltimore, MD 21205, United States
| | - Katherine L Seley-Radtke
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, United States
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10
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Tillault AS, Schultz SK, Wieden HJ, Kothe U. Molecular Determinants for 23S rRNA Recognition and Modification by the E. coli Pseudouridine Synthase RluE. J Mol Biol 2018; 430:1284-1294. [PMID: 29555553 DOI: 10.1016/j.jmb.2018.03.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/25/2018] [Accepted: 03/13/2018] [Indexed: 11/18/2022]
Abstract
The isomerization of uridine to pseudouridine is the most common type of RNA modification found in RNAs across all domains of life and is performed by RNA-dependent and RNA-independent enzymes. The Escherichia coli pseudouridine synthase RluE acts as a stand-alone, highly specific enzyme forming the universally conserved pseudouridine at position 2457, located in helix 89 (H89) of the 23S rRNA in the peptidyltransferase center. Here, we conduct a detailed structure-function analysis to determine the structural elements both in RluE and in 23S rRNA required for RNA-protein interaction and pseudouridine formation. We determined that RluE recognizes a large part of 23S rRNA comprising both H89 and the single-stranded flanking regions which explains the high substrate specificity of RluE. Within RluE, the target RNA is recognized through sequence-specific contacts with loop L7-8 as well as interactions with loop L1-2 and the flexible N-terminal region. We demonstrate that RluE is a faster pseudouridine synthase than other enzymes which likely enables it to act in the early stages of ribosome formation. In summary, our biochemical characterization of RluE provides detailed insight into the molecular mechanism of RluE forming a highly conserved pseudouridine during ribosome biogenesis.
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Affiliation(s)
- Anne-Sophie Tillault
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Sarah K Schultz
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Hans-Joachim Wieden
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada
| | - Ute Kothe
- Alberta RNA Research and Training Institute, Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, AB, T1K 3M4, Canada.
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11
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Mackenzie HW, Hansen DF. A 13C-detected 15N double-quantum NMR experiment to probe arginine side-chain guanidinium 15N η chemical shifts. JOURNAL OF BIOMOLECULAR NMR 2017; 69:123-132. [PMID: 29127559 PMCID: PMC5711973 DOI: 10.1007/s10858-017-0137-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 09/25/2017] [Indexed: 05/25/2023]
Abstract
Arginine side-chains are often key for enzyme catalysis, protein-ligand and protein-protein interactions. The importance of arginine stems from the ability of the terminal guanidinium group to form many key interactions, such as hydrogen bonds and salt bridges, as well as its perpetual positive charge. We present here an arginine 13Cζ-detected NMR experiment in which a double-quantum coherence involving the two 15Nη nuclei is evolved during the indirect chemical shift evolution period. As the precession frequency of the double-quantum coherence is insensitive to exchange of the two 15Nη; this new approach is shown to eliminate the previously deleterious line broadenings of 15Nη resonances caused by the partially restricted rotation about the Cζ-Nε bond. Consequently, sharp and well-resolved 15Nη resonances can be observed. The utility of the presented method is demonstrated on the L99A mutant of the 19 kDa protein T4 lysozyme, where the measurement of small chemical shift perturbations, such as one-bond deuterium isotope shifts, of the arginine amine 15Nη nuclei becomes possible using the double-quantum experiment.
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Affiliation(s)
- Harold W Mackenzie
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, UK
| | - D Flemming Hansen
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, London, WC1E 6BT, UK.
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12
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Schmid K, Adobes-Vidal M, Helm M. Alkyne-Functionalized Coumarin Compound for Analytic and Preparative 4-Thiouridine Labeling. Bioconjug Chem 2017; 28:1123-1134. [PMID: 28263563 DOI: 10.1021/acs.bioconjchem.7b00035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bioconjugation of RNA is a dynamic field recently reinvigorated by a surge in research on post-transcriptional modification. This work focuses on the bioconjugation of 4-thiouridine, a nucleoside that occurs as a post-transcriptional modification in bacterial RNA and is used as a metabolic label and for cross-linking purposes in eukaryotic RNA. A newly designed coumarin compound named 4-bromomethyl-7-propargyloxycoumarin (PBC) is introduced, which exhibits remarkable selectivity for 4-thiouridine. Bearing a terminal alkyne group, it is conductive to secondary bioconjugation via "click chemistry", thereby offering a wide range of preparative and analytical options. We applied PBC to quantitatively monitor the metabolic incorporation of s4U as a label into RNA and for site-specific introduction of a fluorophore into bacterial tRNA at position 8, allowing the determination of its binding constant to an RNA-modification enzyme.
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Affiliation(s)
- Katharina Schmid
- Institute of Pharmacy and Biochemistry, Johannes-Gutenberg University Mainz , Staudingerweg 5, D-55128 Mainz, Germany
| | - Maria Adobes-Vidal
- Electrochemistry & Interfaces Group, Department of Chemistry, University of Warwick , Coventry, CV4 7AL United Kingdom
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, Johannes-Gutenberg University Mainz , Staudingerweg 5, D-55128 Mainz, Germany
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13
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Abstract
Cellular RNAs are chemically modified by many RNA modification enzymes; however, often the functions of modifications remain unclear, such as for pseudouridine formation in the tRNA TΨC arm by the bacterial tRNA pseudouridine synthase TruB. Here we test the hypothesis that RNA modification enzymes also act as RNA chaperones. Using TruB as a model, we demonstrate that TruB folds tRNA independent of its catalytic activity, thus increasing the fraction of tRNA that can be aminoacylated. By rapid kinetic stopped-flow analysis, we identified the molecular mechanism of TruB's RNA chaperone activity: TruB binds and unfolds both misfolded and folded tRNAs thereby providing misfolded tRNAs a second chance at folding. Previously, it has been shown that a catalytically inactive TruB variant has no phenotype when expressed in an Escherichia coli truB KO strain [Gutgsell N, et al. (2000) RNA 6(12):1870-1881]. However, here we uncover that E. coli strains expressing a TruB variant impaired in tRNA binding and in in vitro tRNA folding cannot compete with WT E. coli. Consequently, the tRNA chaperone activity of TruB is critical for bacterial fitness. In conclusion, we prove the tRNA chaperone activity of the pseudouridine synthase TruB, reveal its molecular mechanism, and demonstrate its importance for cellular fitness. We discuss the likelihood that other RNA modification enzymes are also RNA chaperones.
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14
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Addepalli B, Limbach PA. Pseudouridine in the Anticodon of Escherichia coli tRNATyr(QΨA) Is Catalyzed by the Dual Specificity Enzyme RluF. J Biol Chem 2016; 291:22327-22337. [PMID: 27551044 DOI: 10.1074/jbc.m116.747865] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Indexed: 02/02/2023] Open
Abstract
Pseudouridine is found in almost all cellular ribonucleic acids (RNAs). Of the multiple characteristics attributed to pseudouridine, making messenger RNAs (mRNAs) highly translatable and non-immunogenic is one such feature that directly implicates this modification in protein synthesis. We report the existence of pseudouridine in the anticodon of Escherichia coli tyrosine transfer RNAs (tRNAs) at position 35. Pseudouridine was verified by multiple detection methods, which include pseudouridine-specific chemical derivatization and gas phase dissociation of RNA during liquid chromatography tandem mass spectrometry (LC-MS/MS). Analysis of total tRNA isolated from E. coli pseudouridine synthase knock-out mutants identified RluF as the enzyme responsible for this modification. Furthermore, the absence of this modification compromises the translational ability of a luciferase reporter gene coding sequence when it is preceded by multiple tyrosine codons. This effect has implications for the translation of mRNAs that are rich in tyrosine codons in bacterial expression systems.
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Affiliation(s)
- Balasubrahmanyam Addepalli
- From the Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, Ohio 45221
| | - Patrick A Limbach
- From the Department of Chemistry, Rieveschl Laboratories for Mass Spectrometry, University of Cincinnati, Cincinnati, Ohio 45221
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Spenkuch F, Hinze G, Kellner S, Kreutz C, Micura R, Basché T, Helm M. Dye label interference with RNA modification reveals 5-fluorouridine as non-covalent inhibitor. Nucleic Acids Res 2014; 42:12735-45. [PMID: 25300485 PMCID: PMC4227767 DOI: 10.1093/nar/gku908] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The interest in RNA modification enzymes surges due to their involvement in epigenetic phenomena. Here we present a particularly informative approach to investigate the interaction of dye-labeled RNA with modification enzymes. We investigated pseudouridine (Ψ) synthase TruB interacting with an alleged suicide substrate RNA containing 5-fluorouridine (5FU). A longstanding dogma, stipulating formation of a stable covalent complex was challenged by discrepancies between the time scale of complex formation and enzymatic turnover. Instead of classic mutagenesis, we used differentially positioned fluorescent labels to modulate substrate properties in a range of enzymatic conversion between 6% and 99%. Despite this variegation, formation of SDS-stable complexes occurred instantaneously for all 5FU-substrates. Protein binding was investigated by advanced fluorescence spectroscopy allowing unprecedented simultaneous detection of change in fluorescence lifetime, anisotropy decay, as well as emission and excitation maxima. Determination of Kd values showed that introduction of 5FU into the RNA substrate increased protein affinity by 14× at most. Finally, competition experiments demonstrated reversibility of complex formation for 5FU-RNA. Our results lead us to conclude that the hitherto postulated long-term covalent interaction of TruB with 5FU tRNA is based on the interpretation of artifacts. This is likely true for the entire class of pseudouridine synthases.
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Affiliation(s)
- Felix Spenkuch
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
| | - Gerald Hinze
- Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Stefanie Kellner
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
| | - Christoph Kreutz
- Institute of Organic Chemistry, Center for Molecular Biosciences (CMBI), University of Innsbruck, Innrain 52A, A-60230 Innsbruck, Austria
| | - Ronald Micura
- Institute of Organic Chemistry, Center for Chemistry and Biomedicine - CCB, University of Innsbruck, Innrain 80/82, A-60230 Innsbruck, Austria
| | - Thomas Basché
- Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Mark Helm
- Institute of Pharmacy and Biochemistry, University of Mainz, Staudingerweg 5, D-55128 Mainz, Germany
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Spenkuch F, Motorin Y, Helm M. Pseudouridine: still mysterious, but never a fake (uridine)! RNA Biol 2014; 11:1540-54. [PMID: 25616362 PMCID: PMC4615568 DOI: 10.4161/15476286.2014.992278] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/23/2014] [Accepted: 10/10/2014] [Indexed: 01/15/2023] Open
Abstract
Pseudouridine (Ψ) is the most abundant of >150 nucleoside modifications in RNA. Although Ψ was discovered as the first modified nucleoside more than half a century ago, neither the enzymatic mechanism of its formation, nor the function of this modification are fully elucidated. We present the consistent picture of Ψ synthases, their substrates and their substrate positions in model organisms of all domains of life as it has emerged to date and point out the challenges that remain concerning higher eukaryotes and the elucidation of the enzymatic mechanism.
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MESH Headings
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Humans
- Intramolecular Transferases/genetics
- Intramolecular Transferases/metabolism
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Nucleic Acid Conformation
- Pseudouridine/metabolism
- RNA/genetics
- RNA/metabolism
- RNA Processing, Post-Transcriptional
- RNA, Mitochondrial
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer, Amino Acid-Specific/chemistry
- RNA, Transfer, Amino Acid-Specific/genetics
- RNA, Transfer, Amino Acid-Specific/metabolism
- Ribonucleoproteins, Small Nuclear/genetics
- Ribonucleoproteins, Small Nuclear/metabolism
- Ribosomes/chemistry
- Ribosomes/metabolism
- Saccharomyces cerevisiae/genetics
- Saccharomyces cerevisiae/metabolism
- Uridine/metabolism
- RNA, Guide, CRISPR-Cas Systems
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Affiliation(s)
- Felix Spenkuch
- Institute of Pharmacy and Biochemistry; Johannes Gutenberg-University of Mainz; Mainz, Germany
| | - Yuri Motorin
- Laboratoire IMoPA; Ingénierie Moléculaire et Physiopathologie Articulaire; BioPôle de l'Université de Lorraine; Campus Biologie-Santé; Faculté de Médecine; Vandoeuvre-les-Nancy Cedex, France
| | - Mark Helm
- Institute of Pharmacy and Biochemistry; Johannes Gutenberg-University of Mainz; Mainz, Germany
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