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Nakamura T, Yamagata Y. Visualization of mutagenic nucleotide processing by Escherichia coli MutT, a Nudix hydrolase. Proc Natl Acad Sci U S A 2022; 119:e2203118119. [PMID: 35594391 PMCID: PMC9173781 DOI: 10.1073/pnas.2203118119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/09/2022] [Indexed: 11/18/2022] Open
Abstract
Escherichia coli MutT prevents mutations by hydrolyzing mutagenic 8-oxo-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP) in the presence of Mg2+ or Mn2+ ions. MutT is one of the most studied enzymes in the nucleoside diphosphate-linked moiety X (Nudix) hydrolase superfamily, which is widely distributed in living organisms. However, the catalytic mechanisms of most Nudix hydrolases, including two- or three-metal-ion mechanisms, are still unclear because these mechanisms are proposed using the structures mimicking the reaction states, such as substrate analog complexes. Here, we visualized the hydrolytic reaction process of MutT by time-resolved X-ray crystallography using a biological substrate, 8-oxo-dGTP, and an active metal ion, Mn2+. The reaction was initiated by soaking MutT crystals in a MnCl2 solution and stopped by freezing the crystals at various time points. In total, five types of intermediate structures were refined by investigating the time course of the electron densities in the active site as well as the anomalous signal intensities of Mn2+ ions. The structures and electron densities show that three Mn2+ ions bind to the Nudix motif of MutT and align the substrate 8-oxo-dGTP for catalysis. Accompanied by the coordination of the three Mn2+ ions, a water molecule, bound to a catalytic base, forms a binuclear Mn2+ center for nucleophilic substitution at the β-phosphorus of 8-oxo-dGTP. The reaction condition using Mg2+ also captured a structure in complex with three Mg2+ ions. This study provides the structural details essential for understanding the three-metal-ion mechanism of Nudix hydrolases and proposes that some of the Nudix hydrolases share this mechanism.
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Affiliation(s)
- Teruya Nakamura
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto, 862-0973, Japan
| | - Yuriko Yamagata
- Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan
- Shokei University and Shokei University Junior College, Kumamoto, 862-8678, Japan
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2
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A distinct RNA recognition mechanism governs Np4 decapping by RppH. Proc Natl Acad Sci U S A 2022; 119:2117318119. [PMID: 35131855 PMCID: PMC8833179 DOI: 10.1073/pnas.2117318119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2021] [Indexed: 01/15/2023] Open
Abstract
Dinucleoside tetraphosphate alarmones function in bacteria as precursors to 5′-terminal nucleoside tetraphosphate (Np4) caps, becoming incorporated at high levels into RNA during stress and thereby influencing transcript lifetimes. However, little is known about how these noncanonical caps are removed as a prelude to RNA degradation. Here, we report that the RNA pyrophosphohydrolase RppH assumes a leading role in decapping those transcripts under conditions of disulfide stress and that it recognizes Np4-capped 5′ ends by an unexpected mechanism, generating a triphosphorylated RNA intermediate that must undergo further deprotection by RppH to trigger degradation. These findings help to explain the uneven distribution of Np4 caps on bacterial transcripts and have important implications for how gene expression is reprogrammed in response to stress. Dinucleoside tetraphosphates, often described as alarmones because their cellular concentration increases in response to stress, have recently been shown to function in bacteria as precursors to nucleoside tetraphosphate (Np4) RNA caps. Removal of this cap is critical for initiating 5′ end-dependent degradation of those RNAs, potentially affecting bacterial adaptability to stress; however, the predominant Np4 decapping enzyme in proteobacteria, ApaH, is inactivated by the very conditions of disulfide stress that enable Np4-capped RNAs to accumulate to high levels. Here, we show that, in Escherichia coli cells experiencing such stress, the RNA pyrophosphohydrolase RppH assumes a leading role in decapping those transcripts, preferring them as substrates over their triphosphorylated and diphosphorylated counterparts. Unexpectedly, this enzyme recognizes Np4-capped 5′ ends by a mechanism distinct from the one it uses to recognize other 5′ termini, resulting in a one-nucleotide shift in substrate specificity. The unique manner in which capped substrates of this kind bind to the active site of RppH positions the δ-phosphate, rather than the β-phosphate, for hydrolytic attack, generating triphosphorylated RNA as the primary product of decapping. Consequently, a second RppH-catalyzed deprotection step is required to produce the monophosphorylated 5′ terminus needed to stimulate rapid RNA decay. The unconventional manner in which RppH recognizes Np4-capped 5′ ends and its differential impact on the rates at which such termini are deprotected as a prelude to RNA degradation could have major consequences for reprogramming gene expression during disulfide stress.
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Jones RA, Steckelberg AL, Vicens Q, Szucs MJ, Akiyama BM, Kieft JS. Different tertiary interactions create the same important 3D features in a distinct flavivirus xrRNA. RNA (NEW YORK, N.Y.) 2021; 27:54-65. [PMID: 33004436 PMCID: PMC7749634 DOI: 10.1261/rna.077065.120] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 09/27/2020] [Indexed: 05/12/2023]
Abstract
During infection by a flavivirus (FV), cells accumulate noncoding subgenomic flavivirus RNAs (sfRNAs) that interfere with several antiviral pathways. These sfRNAs are formed by structured RNA elements in the 3' untranslated region (UTR) of the viral genomic RNA, which block the progression of host cell exoribonucleases that have targeted the viral RNA. Previous work on these exoribonuclease-resistant RNAs (xrRNAs) from mosquito-borne FVs revealed a specific three-dimensional fold with a unique topology in which a ring-like structure protectively encircles the 5' end of the xrRNA. Conserved nucleotides make specific tertiary interactions that support this fold. Examination of more divergent FVs reveals differences in their 3' UTR sequences, raising the question of whether they contain xrRNAs and if so, how they fold. To answer this, we demonstrated the presence of an authentic xrRNA in the 3' UTR of the Tamana bat virus (TABV) and solved its structure by X-ray crystallography. The structure reveals conserved features from previously characterized xrRNAs, but in the TABV version these features are created through a novel set of tertiary interactions not previously seen in xrRNAs. This includes two important A-C interactions, four distinct backbone kinks, several ordered Mg2+ ions, and a C+-G-C base triple. The discovery that the same overall architecture can be achieved by very different sequences and interactions in distantly related flaviviruses provides insight into the diversity of this type of RNA and will inform searches for undiscovered xrRNAs in viruses and beyond.
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MESH Headings
- 3' Untranslated Regions
- Animals
- Base Pairing
- Base Sequence
- Cations, Divalent
- Crystallography, X-Ray
- Encephalitis Virus, Murray Valley/genetics
- Encephalitis Virus, Murray Valley/metabolism
- Encephalitis Virus, Murray Valley/ultrastructure
- Exoribonucleases/chemistry
- Exoribonucleases/metabolism
- Flaviviridae/genetics
- Flaviviridae/metabolism
- Flaviviridae/ultrastructure
- Host-Pathogen Interactions/genetics
- Magnesium/chemistry
- Magnesium/metabolism
- RNA Folding
- RNA, Untranslated/chemistry
- RNA, Untranslated/genetics
- RNA, Untranslated/metabolism
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Viruses, Unclassified/genetics
- Viruses, Unclassified/metabolism
- Viruses, Unclassified/ultrastructure
- Zika Virus/genetics
- Zika Virus/metabolism
- Zika Virus/ultrastructure
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Affiliation(s)
- Rachel A Jones
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Anna-Lena Steckelberg
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Matthew J Szucs
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin M Akiyama
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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4
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Steckelberg AL, Vicens Q, Costantino DA, Nix JC, Kieft JS. The crystal structure of a Polerovirus exoribonuclease-resistant RNA shows how diverse sequences are integrated into a conserved fold. RNA (NEW YORK, N.Y.) 2020; 26:1767-1776. [PMID: 32848042 PMCID: PMC7668246 DOI: 10.1261/rna.076224.120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/19/2020] [Indexed: 05/31/2023]
Abstract
Exoribonuclease-resistant RNAs (xrRNAs) are discrete elements that block the progression of 5' to 3' exoribonucleases using specifically folded RNA structures. A recently discovered class of xrRNA is widespread in several genera of plant-infecting viruses, within both noncoding and protein-coding subgenomic RNAs. The structure of one such xrRNA from a dianthovirus revealed three-dimensional details of the resistant fold but did not answer all questions regarding the conservation and diversity of this xrRNA class. Here, we present the crystal structure of a representative polerovirus xrRNA that contains sequence elements that diverge from the previously solved structure. This new structure rationalizes previously unexplained sequence conservation patterns and shows interactions not present in the first structure. Together, the structures of these xrRNAs from dianthovirus and polerovirus genera support the idea that these plant virus xrRNAs fold through a defined pathway that includes a programmed intermediate conformation. This work deepens our knowledge of the structure-function relationship of xrRNAs and shows how evolution can craft similar RNA folds from divergent sequences.
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Affiliation(s)
- Anna-Lena Steckelberg
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - David A Costantino
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jay C Nix
- Molecular Biology Consortium, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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5
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Steckelberg AL, Vicens Q, Costantino DA, Nix JC, Kieft JS. The crystal structure of a Polerovirus exoribonuclease-resistant RNA shows how diverse sequences are integrated into a conserved fold. RNA (NEW YORK, N.Y.) 2020; 26:1767-1776. [PMID: 32848042 DOI: 10.1101/2020.04.30.070631] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/19/2020] [Indexed: 05/26/2023]
Abstract
Exoribonuclease-resistant RNAs (xrRNAs) are discrete elements that block the progression of 5' to 3' exoribonucleases using specifically folded RNA structures. A recently discovered class of xrRNA is widespread in several genera of plant-infecting viruses, within both noncoding and protein-coding subgenomic RNAs. The structure of one such xrRNA from a dianthovirus revealed three-dimensional details of the resistant fold but did not answer all questions regarding the conservation and diversity of this xrRNA class. Here, we present the crystal structure of a representative polerovirus xrRNA that contains sequence elements that diverge from the previously solved structure. This new structure rationalizes previously unexplained sequence conservation patterns and shows interactions not present in the first structure. Together, the structures of these xrRNAs from dianthovirus and polerovirus genera support the idea that these plant virus xrRNAs fold through a defined pathway that includes a programmed intermediate conformation. This work deepens our knowledge of the structure-function relationship of xrRNAs and shows how evolution can craft similar RNA folds from divergent sequences.
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Affiliation(s)
- Anna-Lena Steckelberg
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Quentin Vicens
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - David A Costantino
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
| | - Jay C Nix
- Molecular Biology Consortium, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, USA
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6
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Vargas-Blanco DA, Shell SS. Regulation of mRNA Stability During Bacterial Stress Responses. Front Microbiol 2020; 11:2111. [PMID: 33013770 PMCID: PMC7509114 DOI: 10.3389/fmicb.2020.02111] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/11/2020] [Indexed: 12/12/2022] Open
Abstract
Bacteria have a remarkable ability to sense environmental changes, swiftly regulating their transcriptional and posttranscriptional machinery as a response. Under conditions that cause growth to slow or stop, bacteria typically stabilize their transcriptomes in what has been shown to be a conserved stress response. In recent years, diverse studies have elucidated many of the mechanisms underlying mRNA degradation, yet an understanding of the regulation of mRNA degradation under stress conditions remains elusive. In this review we discuss the diverse mechanisms that have been shown to affect mRNA stability in bacteria. While many of these mechanisms are transcript-specific, they provide insight into possible mechanisms of global mRNA stabilization. To that end, we have compiled information on how mRNA fate is affected by RNA secondary structures; interaction with ribosomes, RNA binding proteins, and small RNAs; RNA base modifications; the chemical nature of 5' ends; activity and concentration of RNases and other degradation proteins; mRNA and RNase localization; and the stringent response. We also provide an analysis of reported relationships between mRNA abundance and mRNA stability, and discuss the importance of stress-associated mRNA stabilization as a potential target for therapeutic development.
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Affiliation(s)
- Diego A Vargas-Blanco
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States
| | - Scarlet S Shell
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA, United States.,Program in Bioinformatics and Computational Biology, Worcester Polytechnic Institute, Worcester, MA, United States
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7
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Drabinska J, Ziecina M, Modzelan M, Jagura‐Burdzy G, Kraszewska E. Individual Nudix hydrolases affect diverse features of Pseudomonas aeruginosa. Microbiologyopen 2020; 9:e1052. [PMID: 32419387 PMCID: PMC7424265 DOI: 10.1002/mbo3.1052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/10/2020] [Accepted: 04/10/2020] [Indexed: 12/20/2022] Open
Abstract
Nudix proteins catalyze the hydrolysis of pyrophosphate bonds in a variety of substrates and are ubiquitous in all domains of life. The genome of an important opportunistic human pathogen, Pseudomonas aeruginosa, encodes multiple Nudix proteins. To determine the role of nine Nudix hydrolases of the P. aeruginosa PAO1161 strain in its fitness, virulence or antibiotic resistance mutants devoid of individual enzymes were constructed and analyzed for growth rate, motility, biofilm formation, pyocyanin production, and susceptibility to oxidative stress and different antibiotics. The potential effect on bacterial virulence was studied using the Caenorhabditis elegans-P. aeruginosa infection model. Of the nine mutants tested, five had an altered phenotype in comparison with the wild-type strain. The ΔPA3470, ΔPA3754, and ΔPA4400 mutants showed increased pyocyanin production, were more resistant to the β-lactam antibiotic piperacillin, and were more sensitive to killing by H2 O2 . In addition, ΔPA4400 and ΔPA5176 had impaired swarming motility and were less virulent for C. elegans. The ΔPA4841 had an increased sensitivity to oxidative stress. These changes were reversed by providing the respective nudix gene in trans indicating that the observed phenotype alterations were indeed due to the lack of the particular Nudix protein.
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Affiliation(s)
| | | | - Marta Modzelan
- Institute of Biochemistry and Biophysics PASWarsawPoland
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8
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Gao A, Vasilyev N, Kaushik A, Duan W, Serganov A. Principles of RNA and nucleotide discrimination by the RNA processing enzyme RppH. Nucleic Acids Res 2020; 48:3776-3788. [PMID: 31960065 PMCID: PMC7144940 DOI: 10.1093/nar/gkaa024] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 01/06/2020] [Accepted: 01/18/2020] [Indexed: 12/23/2022] Open
Abstract
All enzymes face a challenge of discriminating cognate substrates from similar cellular compounds. Finding a correct substrate is especially difficult for the Escherichia coli Nudix hydrolase RppH, which triggers 5'-end-dependent RNA degradation by removing orthophosphate from the 5'-diphosphorylated transcripts. Here we show that RppH binds and slowly hydrolyzes NTPs, NDPs and (p)ppGpp, which each resemble the 5'-end of RNA. A series of X-ray crystal structures of RppH-nucleotide complexes, trapped in conformations either compatible or incompatible with hydrolysis, explain the low reaction rates of mononucleotides and suggest two distinct mechanisms for their hydrolysis. While RppH adopts the same catalytic arrangement with 5'-diphosphorylated nucleotides as with RNA, the enzyme hydrolyzes 5'-triphosphorylated nucleotides by extending the active site with an additional Mg2+ cation, which coordinates another reactive nucleophile. Although the average intracellular pH minimizes the hydrolysis of nucleotides by slowing their reaction with RppH, they nevertheless compete with RNA for binding and differentially inhibit the reactivity of RppH with triphosphorylated and diphosphorylated RNAs. Thus, E. coli RppH integrates various signals, such as competing non-cognate substrates and a stimulatory protein factor DapF, to achieve the differential degradation of transcripts involved in cellular processes important for the adaptation of bacteria to different growth conditions.
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Affiliation(s)
- Ang Gao
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Nikita Vasilyev
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Abhishek Kaushik
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Wenqian Duan
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Alexander Serganov
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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9
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Langeberg CJ, Welch WRW, McGuire JV, Ashby A, Jackson AD, Chapman EG. Biochemical Characterization of Yeast Xrn1. Biochemistry 2020; 59:1493-1507. [PMID: 32251580 DOI: 10.1021/acs.biochem.9b01035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Messenger RNA degradation is an important component of overall gene expression. During the final step of eukaryotic mRNA degradation, exoribonuclease 1 (Xrn1) carries out 5' → 3' processive, hydrolytic degradation of RNA molecules using divalent metal ion catalysis. To initiate studies of the 5' → 3' RNA decay machinery in our lab, we expressed a C-terminally truncated version of Saccharomyces cerevisiae Xrn1 and explored its enzymology using a second-generation, time-resolved fluorescence RNA degradation assay. Using this system, we quantitatively explored Xrn1's preference for 5'-monophosphorylated RNA substrates, its pH dependence, and the importance of active site mutations in the molecule's conserved catalytic core. Furthermore, we explore Xrn1's preference for RNAs containing a 5' single-stranded region both in an intermolecular hairpin structure and in an RNA-DNA hybrid duplex system. These results both expand and solidify our understanding of Xrn1, a centrally important enzyme whose biochemical properties have implications in numerous RNA degradation and processing pathways.
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Affiliation(s)
- Conner J Langeberg
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - William R W Welch
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - John V McGuire
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Alison Ashby
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Alexander D Jackson
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
| | - Erich G Chapman
- Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208, United States
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10
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Short Direct Repeats in the 3' Untranslated Region Are Involved in Subgenomic Flaviviral RNA Production. J Virol 2020; 94:JVI.01175-19. [PMID: 31896596 DOI: 10.1128/jvi.01175-19] [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: 07/16/2019] [Accepted: 12/18/2019] [Indexed: 11/20/2022] Open
Abstract
Mosquito-borne flaviviruses consist of a positive-sense genome RNA flanked by the untranslated regions (UTRs). There is a panel of highly complex RNA structures in the UTRs with critical functions. For instance, Xrn1-resistant RNAs (xrRNAs) halt Xrn1 digestion, leading to the production of subgenomic flaviviral RNA (sfRNA). Conserved short direct repeats (DRs), also known as conserved sequences (CS) and repeated conserved sequences (RCS), have been identified as being among the RNA elements locating downstream of xrRNAs, but their biological function remains unknown. In this study, we revealed that the specific DRs are involved in the production of specific sfRNAs in both mammalian and mosquito cells. Biochemical assays and structural remodeling demonstrate that the base pairings in the stem of these DRs control sfRNA formation by maintaining the binding affinity of the corresponding xrRNAs to Xrn1. On the basis of these findings, we propose that DRs functions like a bracket holding the Xrn1-xrRNA complex for sfRNA formation.IMPORTANCE Flaviviruses include many important human pathogens. The production of subgenomic flaviviral RNAs (sfRNAs) is important for viral pathogenicity as a common feature of flaviviruses. sfRNAs are formed through the incomplete degradation of viral genomic RNA by the cytoplasmic 5'-3' exoribonuclease Xrn1 halted at the Xrn1-resistant RNA (xrRNA) structures within the 3'-UTR. The 3'-UTRs of the flavivirus genome also contain distinct short direct repeats (DRs), such as RCS3, CS3, RCS2, and CS2. However, the biological functions of these ancient primary DR sequences remain largely unknown. Here, we found that DR sequences are involved in sfRNA formation and viral virulence and provide novel targets for the rational design of live attenuated flavivirus vaccine.
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11
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Schumacher MA, Henderson M, Zeng W. Structures of MERS1, the 5' processing enzyme of mitochondrial mRNAs in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2020; 26:69-82. [PMID: 31704716 PMCID: PMC6913127 DOI: 10.1261/rna.072231.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/25/2019] [Indexed: 05/05/2023]
Abstract
Most mitochondrial mRNAs are transcribed as polycistronic precursors that are cleaved by endonucleases to produce mature mRNA transcripts. However, recent studies have shown that mitochondrial transcripts in the kinetoplastid protozoan, Trypanosoma brucei, are transcribed individually. Also unlike most mitochondrial mRNAs, the 5' end of these transcripts harbor a triphosphate that is hydrolyzed. This modification is carried out by a putative Nudix hydrolase called MERS1. The Nudix motif in MERS1 is degenerate, lacking a conserved glutamic acid, thus it is unclear how it may bind its substrates and whether it contains a Nudix fold. To obtain insight into this unusual hydrolase, we determined structures of apo, GTP-bound and RNA-bound T. brucei MERS1 to 2.30 Å, 2.45 Å, and 2.60 Å, respectively. The MERS1 structure has a unique fold that indeed contains a Nudix motif. The nucleotide bound structures combined with binding studies reveal that MERS1 shows preference for RNA sequences with a central guanine repeat which it binds in a single-stranded conformation. The apo MERS1 structure indicates that a significant portion of its nucleotide binding site folds upon substrate binding. Finally, a potential interaction region for a binding partner, MERS2, that activates MERS1 was identified. The MERS2-like peptide inserts a glutamate near the missing Nudix acidic residue in the RNA binding pocket, suggesting how the enzyme may be activated. Thus, the combined studies reveal insight into the structure and enzyme properties of MERS1 and its substrate-binding activities.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Max Henderson
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Wenjie Zeng
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina 27710, USA
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12
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Wang Q, Zhang D, Guan Z, Li D, Pei K, Liu J, Zou T, Yin P. DapF stabilizes the substrate-favoring conformation of RppH to stimulate its RNA-pyrophosphohydrolase activity in Escherichia coli. Nucleic Acids Res 2019; 46:6880-6892. [PMID: 29931175 PMCID: PMC6061791 DOI: 10.1093/nar/gky528] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 05/28/2018] [Indexed: 11/30/2022] Open
Abstract
mRNA decay is an important strategy by which bacteria can rapidly adapt to their ever-changing surroundings. The 5′-terminus state of mRNA determines the velocity of decay of many types of RNA. In Escherichia coli, RNA pyrophosphohydrolase (RppH) is responsible for the removal of the 5′-terminal triphosphate from hundreds of mRNAs and triggers its rapid degradation by ribonucleases. A diaminopimelate epimerase, DapF, can directly interact with RppH and stimulate its hydrolysis activity in vivo and in vitro. However, the molecular mechanism remains to be elucidated. Here, we determined the complex structure of DapF–RppH as a heterotetramer in a 2:2 molar ratio. DapF-bound RppH exhibits an RNA-favorable conformation similar to the RNA-bound state, suggesting that association with DapF promotes and stabilizes RppH in a conformation that facilitates substrate RNA binding and thus stimulates the activity of RppH. To our knowledge, this is the first published structure of an RNA–pyrophosphohydrolysis complex in bacteria. Our study provides a framework for further investigation of the potential regulators involved in the RNA–pyrophosphohydrolysis process in prokaryotes.
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Affiliation(s)
- Qiang Wang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Delin Zhang
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Zeyuan Guan
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Dongqin Li
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Kai Pei
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Jian Liu
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Tingting Zou
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
| | - Ping Yin
- National Key Laboratory of Crop Genetic Improvement and National Centre of Plant Gene Research, Huazhong Agricultural University, Wuhan 430070, China
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13
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Kujawa M, Lirski M, Ziecina M, Drabinska J, Modzelan M, Kraszewska E. Nudix-type RNA pyrophosphohydrolase provides homeostasis of virulence factor pyocyanin and functions as a global regulator in Pseudomonas aeruginosa. Mol Microbiol 2017; 106:381-394. [PMID: 28833678 DOI: 10.1111/mmi.13771] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2017] [Indexed: 12/26/2022]
Abstract
The PA0336 protein from Pseudomonas aeruginosa belongs to the family of widely distributed Nudix pyrophosphohydrolases, which catalyze the hydrolysis of pyrophosphate bonds in a variety of nucleoside diphosphate derivatives. The amino acid sequence of the PA0336 protein is highly similar to that of the RppH Nudix RNA pyrophosphohydrolase from Escherichia coli, which removes pyrophosphate from 5'-end of triphosphorylated RNA transcripts. Trans-complementation experiments showed that the P. aeruginosa enzyme can functionally substitute for RppH in E. coli cells indicating that, similar to RppH, the Pseudomonas hydrolase mediates RNA turnover in vivo. In order to elucidate the biological significance of the PA0336 protein in Pseudomonas cells, a PA0336 mutant strain was constructed. The mutated strain considerably increased level of the virulence factor pyocyanin compared to wild type, suggesting that PA0336 could be involved in downregulation of P. aeruginosa pathogenicity. This phenotype was reversed by complementation with the wild type but not catalytically inactive PA0336, indicating that the catalytic activity was indispensable for its biological function. Pathogenesis tests in Caenorhabditis elegans showed that the PA0336 mutant of P. aeruginosa was significantly more virulent than the parental strain, confirming further that the P. aeruginosa RNA pyrophosphohydrolase PA0336 modulates bacterial pathogenesis by down-regulating production of virulence-associated factors. To study the role of PA0336 further, transcriptomes of the PA0336 mutant and the wild-type strain were compared using RNA sequencing. The level of 537 transcripts coding for proteins involved in a variety of cellular processes such as replication, transcription, translation, central metabolism and pathogenesis, was affected by the lack of PA0336. These results indicate that the PA0336 RNA pyrophosphohydrolase functions as a global regulator that influences many of transcripts including those involved in P. aeruginosa virulence.
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Affiliation(s)
- Martyna Kujawa
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Maciej Lirski
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Mateusz Ziecina
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Joanna Drabinska
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Marta Modzelan
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
| | - Elzbieta Kraszewska
- Institute of Biochemistry and Biophysics PAS, Pawińskiego 5A, 02-106 Warsaw, Poland
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14
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Srouji JR, Xu A, Park A, Kirsch JF, Brenner SE. The evolution of function within the Nudix homology clan. Proteins 2017; 85:775-811. [PMID: 27936487 PMCID: PMC5389931 DOI: 10.1002/prot.25223] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 10/15/2016] [Accepted: 11/28/2016] [Indexed: 01/01/2023]
Abstract
The Nudix homology clan encompasses over 80,000 protein domains from all three domains of life, defined by homology to each other. Proteins with a domain from this clan fall into four general functional classes: pyrophosphohydrolases, isopentenyl diphosphate isomerases (IDIs), adenine/guanine mismatch-specific adenine glycosylases (A/G-specific adenine glycosylases), and nonenzymatic activities such as protein/protein interaction and transcriptional regulation. The largest group, pyrophosphohydrolases, encompasses more than 100 distinct hydrolase specificities. To understand the evolution of this vast number of activities, we assembled and analyzed experimental and structural data for 205 Nudix proteins collected from the literature. We corrected erroneous functions or provided more appropriate descriptions for 53 annotations described in the Gene Ontology Annotation database in this family, and propose 275 new experimentally-based annotations. We manually constructed a structure-guided sequence alignment of 78 Nudix proteins. Using the structural alignment as a seed, we then made an alignment of 347 "select" Nudix homology domains, curated from structurally determined, functionally characterized, or phylogenetically important Nudix domains. Based on our review of Nudix pyrophosphohydrolase structures and specificities, we further analyzed a loop region downstream of the Nudix hydrolase motif previously shown to contact the substrate molecule and possess known functional motifs. This loop region provides a potential structural basis for the functional radiation and evolution of substrate specificity within the hydrolase family. Finally, phylogenetic analyses of the 347 select protein domains and of the complete Nudix homology clan revealed general monophyly with regard to function and a few instances of probable homoplasy. Proteins 2017; 85:775-811. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- John R. Srouji
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMassachusetts02138
| | - Anting Xu
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
| | - Steven E. Brenner
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Study in Comparative Biochemistry, University of CaliforniaBerkeleyCalifornia94720
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15
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Arif SM, Patil AG, Varshney U, Vijayan M. Biochemical and structural studies of Mycobacterium smegmatis MutT1, a sanitization enzyme with unusual modes of association. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2017; 73:349-364. [PMID: 28375146 DOI: 10.1107/s2059798317002534] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 02/14/2017] [Indexed: 01/12/2023]
Abstract
Mycobacterium smegmatis MutT1, which is made up of a Nudix domain (domain 1) and a histidine phosphatase domain (domain 2), efficiently hydrolyses 8-oxo-GTP and 8-oxo-dGTP to the corresponding nucleoside diphosphates and phosphate in the presence of magnesium ions. Domain 1 alone hydrolyses nucleoside triphosphates less efficiently. Under high concentrations and over long periods, the full-length enzyme as well as domain 1 catalyses the hydrolysis of the nucleoside triphosphates to the respective nucleoside monophosphates and pyrophosphate. The role of domain 2 appears to be limited to speeding up the reaction. Crystal structures of the apoenzyme and those of ligand-bound enzyme prepared in the presence of 8-oxo-GTP or 8-oxo-dGTP and different concentrations of magnesium were determined. In all of the structures except one, the molecules arrange themselves in a head-to-tail fashion in which domain 1 is brought into contact with domain 2 (trans domain 2) of a neighbouring molecule. The binding site for NTP (site A) is almost exclusively made up of residues from domain 1, while those for NDP (site B) and NMP (site C) are at the interface between domain 1 and trans domain 2 in an unusual instance of intermolecular interactions leading to binding sites. Protein-ligand interactions at site A lead to a proposal for the mechanism of hydrolysis of NTP to NDP and phosphate. A small modification in site A in the crystal which does not exhibit the head-to-tail arrangement appears to facilitate the production of NMP and pyrophosphate from NTP. The two arrangements could be in dynamic equilibrium in the cellular milieu.
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Affiliation(s)
- S M Arif
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
| | - A G Patil
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - U Varshney
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | - M Vijayan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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16
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Bischler T, Hsieh PK, Resch M, Liu Q, Tan HS, Foley PL, Hartleib A, Sharma CM, Belasco JG. Identification of the RNA Pyrophosphohydrolase RppH of Helicobacter pylori and Global Analysis of Its RNA Targets. J Biol Chem 2016; 292:1934-1950. [PMID: 27974459 DOI: 10.1074/jbc.m116.761171] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/02/2016] [Indexed: 12/20/2022] Open
Abstract
RNA degradation is crucial for regulating gene expression in all organisms. Like the decapping of eukaryotic mRNAs, the conversion of the 5'-terminal triphosphate of bacterial transcripts to a monophosphate can trigger RNA decay by exposing the transcript to attack by 5'-monophosphate-dependent ribonucleases. In both biological realms, this deprotection step is catalyzed by members of the Nudix hydrolase family. The genome of the gastric pathogen Helicobacter pylori, a Gram-negative epsilonproteobacterium, encodes two proteins resembling Nudix enzymes. Here we present evidence that one of them, HP1228 (renamed HpRppH), is an RNA pyrophosphohydrolase that triggers RNA degradation in H. pylori, whereas the other, HP0507, lacks such activity. In vitro, HpRppH converts RNA 5'-triphosphates and diphosphates to monophosphates. It requires at least two unpaired nucleotides at the 5' end of its substrates and prefers three or more but has only modest sequence preferences. The influence of HpRppH on RNA degradation in vivo was examined by using RNA-seq to search the H. pylori transcriptome for RNAs whose 5'-phosphorylation state and cellular concentration are governed by this enzyme. Analysis of cDNA libraries specific for transcripts bearing a 5'-triphosphate and/or monophosphate revealed at least 63 potential HpRppH targets. These included mRNAs and sRNAs, several of which were validated individually by half-life measurements and quantification of their 5'-terminal phosphorylation state in wild-type and mutant cells. These findings demonstrate an important role for RppH in post-transcriptional gene regulation in pathogenic Epsilonproteobacteria and suggest a possible basis for the phenotypes of H. pylori mutants lacking this enzyme.
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Affiliation(s)
- Thorsten Bischler
- From the Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany; the Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany and
| | - Ping-Kun Hsieh
- the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Marcus Resch
- From the Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany; the Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany and
| | - Quansheng Liu
- the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Hock Siew Tan
- the Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany and
| | - Patricia L Foley
- the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Anika Hartleib
- From the Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany; the Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany and
| | - Cynthia M Sharma
- From the Research Center for Infectious Diseases, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany; the Institute of Molecular Infection Biology, University of Würzburg, Josef-Schneider-Strasse 2/D15, 97080 Würzburg, Germany and.
| | - Joel G Belasco
- the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016.
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17
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Akiyama BM, Laurence HM, Massey AR, Costantino DA, Xie X, Yang Y, Shi PY, Nix JC, Beckham JD, Kieft JS. Zika virus produces noncoding RNAs using a multi-pseudoknot structure that confounds a cellular exonuclease. Science 2016; 354:1148-1152. [PMID: 27934765 PMCID: PMC5476369 DOI: 10.1126/science.aah3963] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/26/2016] [Indexed: 01/23/2023]
Abstract
The outbreak of Zika virus (ZIKV) and associated fetal microcephaly mandates efforts to understand the molecular processes of infection. Related flaviviruses produce noncoding subgenomic flaviviral RNAs (sfRNAs) that are linked to pathogenicity in fetal mice. These viruses make sfRNAs by co-opting a cellular exonuclease via structured RNAs called xrRNAs. We found that ZIKV-infected monkey and human epithelial cells, mouse neurons, and mosquito cells produce sfRNAs. The RNA structure that is responsible for ZIKV sfRNA production forms a complex fold that is likely found in many pathogenic flaviviruses. Mutations that disrupt the structure affect exonuclease resistance in vitro and sfRNA formation during infection. The complete ZIKV xrRNA structure clarifies the mechanism of exonuclease resistance and identifies features that may modulate function in diverse flaviviruses.
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Affiliation(s)
- Benjamin M Akiyama
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Hannah M Laurence
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
- Howard Hughes Medical Institute (HHMI), University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
- School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Aaron R Massey
- Department of Medicine, Division of Infectious Diseases, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - David A Costantino
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Xuping Xie
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Yujiao Yang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Pei-Yong Shi
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jay C Nix
- Molecular Biology Consortium, Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - J David Beckham
- Department of Medicine, Division of Infectious Diseases, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA.
- RNA BioScience Initiative, University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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18
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Nguyen VN, Park A, Xu A, Srouji JR, Brenner SE, Kirsch JF. Substrate specificity characterization for eight putative nudix hydrolases. Evaluation of criteria for substrate identification within the Nudix family. Proteins 2016; 84:1810-1822. [PMID: 27618147 PMCID: PMC5158307 DOI: 10.1002/prot.25163] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/30/2016] [Accepted: 09/06/2016] [Indexed: 11/16/2022]
Abstract
The nearly 50,000 known Nudix proteins have a diverse array of functions, of which the most extensively studied is the catalyzed hydrolysis of aberrant nucleotide triphosphates. The functions of 171 Nudix proteins have been characterized to some degree, although physiological relevance of the assayed activities has not always been conclusively demonstrated. We investigated substrate specificity for eight structurally characterized Nudix proteins, whose functions were unknown. These proteins were screened for hydrolase activity against a 74-compound library of known Nudix enzyme substrates. We found substrates for four enzymes with kcat /Km values >10,000 M-1 s-1 : Q92EH0_LISIN of Listeria innocua serovar 6a against ADP-ribose, Q5LBB1_BACFN of Bacillus fragilis against 5-Me-CTP, and Q0TTC5_CLOP1 and Q0TS82_CLOP1 of Clostridium perfringens against 8-oxo-dATP and 3'-dGTP, respectively. To ascertain whether these identified substrates were physiologically relevant, we surveyed all reported Nudix hydrolytic activities against NTPs. Twenty-two Nudix enzymes are reported to have activity against canonical NTPs. With a single exception, we find that the reported kcat /Km values exhibited against these canonical substrates are well under 105 M-1 s-1 . By contrast, several Nudix enzymes show much larger kcat /Km values (in the range of 105 to >107 M-1 s-1 ) against noncanonical NTPs. We therefore conclude that hydrolytic activities exhibited by these enzymes against canonical NTPs are not likely their physiological function, but rather the result of unavoidable collateral damage occasioned by the enzymes' inability to distinguish completely between similar substrate structures. Proteins 2016; 84:1810-1822. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Vi N. Nguyen
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Annsea Park
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Anting Xu
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
| | - John R. Srouji
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Present address: Molecular and Cellular Biology DepartmentHarvard UniversityCambridgeMA02138
| | - Steven E. Brenner
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
- Plant and Microbial Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
| | - Jack F. Kirsch
- Molecular and Cell Biology DepartmentUniversity of CaliforniaBerkeleyCalifornia94720
- Graduate Program in Comparative BiochemistryUniversity of CaliforniaBerkeleyCalifornia94720
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19
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Iordanov I, Mihályi C, Tóth B, Csanády L. The proposed channel-enzyme transient receptor potential melastatin 2 does not possess ADP ribose hydrolase activity. eLife 2016; 5. [PMID: 27383051 PMCID: PMC4974056 DOI: 10.7554/elife.17600] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022] Open
Abstract
Transient Receptor Potential Melastatin 2 (TRPM2) is a Ca2+-permeable cation channel essential for immunocyte activation, insulin secretion, and postischemic cell death. TRPM2 is activated by ADP ribose (ADPR) binding to its C-terminal cytosolic NUDT9-homology (NUDT9H) domain, homologous to the soluble mitochondrial ADPR pyrophosphatase (ADPRase) NUDT9. Reported ADPR hydrolysis classified TRPM2 as a channel-enzyme, but insolubility of isolated NUDT9H hampered further investigations. Here we developed a soluble NUDT9H model using chimeric proteins built from complementary polypeptide fragments of NUDT9H and NUDT9. When expressed in E.coli, chimeras containing up to ~90% NUDT9H sequence remained soluble and were affinity-purified. In ADPRase assays the conserved Nudix-box sequence of NUDT9 proved essential for activity (kcat~4-9s-1), that of NUDT9H did not support catalysis. Replacing NUDT9H in full-length TRPM2 with soluble chimeras retained ADPR-dependent channel gating (K1/2~1-5 μM), confirming functionality of chimeric domains. Thus, TRPM2 is not a 'chanzyme'. Chimeras provide convenient soluble NUDT9H models for structural/biochemical studies. DOI:http://dx.doi.org/10.7554/eLife.17600.001 Ion channels are proteins that allow specific charged particles to move across the membranes of cells – for example to travel in or out of a cell, or between different parts of the same cell. Almost all ion channels are gated, meaning that they can open and close in response to different signals. For instance, so-called ligand gated channels open in response to binding of some small molecule, known as the "ligand". A small number of channel proteins are also enzymes, meaning that they are able to catalyze chemical reactions, and these channel-enzymes are often referred to as “chanzymes”. TRPM2 is an ion channel found in humans that opens when a small molecule called ADPR binds to a portion of the channel inside the cell. This channel is also thought to be a chanzyme because the part that binds to ADPR is similar to an enzyme called NUDT9. The NUDT9 enzyme converts ADPR into two other chemicals. When studied in biochemical assays, the enzyme-like part of TRPM2 – which contains a segment called a “Nudix box” – appeared to act in the same way, although this activity was not linked to the opening and closing of the TRPM2 channel. Iordanov et al. set out to re-examine whether TRPM2 is actually an enzyme by comparing the activity of NUDT9 to the enzyme-like part of TRPM2. To test an enzyme’s activity, it typically needs to be dissolved in water. However, the enzyme-like part of TRPM2 does not dissolve, and so it could not be tested directly. Instead, Iordanov et al. identified which parts of TRPM2 make it insoluble and replaced them with the equivalent parts from NUDT9 to create several new proteins. For all the proteins tested, only those with the Nudix box from NUDT9 were active enzymes, while those with the Nudix box from TRPM2 were not. Iordanov et al. conclude that TRPM2 is a ligand gated channel and not a chanzyme, and that the experimental conditions used in previous biochemical assays, and not TRPM2 activity, led to the breakdown of ADPR. Finally, the TRPM2 channel is involved in cell damage following heart attacks or stroke and may contribute to Alzheimer’s disease, Parkinson’s disease and bipolar disorder as well. As such, knowing how TRMP2 behaves could guide efforts to develop new drugs for these illnesses. DOI:http://dx.doi.org/10.7554/eLife.17600.002
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Affiliation(s)
- Iordan Iordanov
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - Csaba Mihályi
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - Balázs Tóth
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
| | - László Csanády
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.,MTA-SE Ion Channel Research Group, Semmelweis University, Budapest, Hungary
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20
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de la Peña AH, Suarez A, Duong-ly KC, Schoeffield AJ, Pizarro-Dupuy MA, Zarr M, Pineiro SA, Amzel LM, Gabelli SB. Structural and Enzymatic Characterization of a Nucleoside Diphosphate Sugar Hydrolase from Bdellovibrio bacteriovorus. PLoS One 2015; 10:e0141716. [PMID: 26524597 PMCID: PMC4629899 DOI: 10.1371/journal.pone.0141716] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 10/12/2015] [Indexed: 11/18/2022] Open
Abstract
Given the broad range of substrates hydrolyzed by Nudix (nucleoside diphosphate linked to X) enzymes, identification of sequence and structural elements that correctly predict a Nudix substrate or characterize a family is key to correctly annotate the myriad of Nudix enzymes. Here, we present the structure determination and characterization of Bd3179 -- a Nudix hydrolase from Bdellovibrio bacteriovorus-that we show localized in the periplasmic space of this obligate Gram-negative predator. We demonstrate that the enzyme is a nucleoside diphosphate sugar hydrolase (NDPSase) and has a high degree of sequence and structural similarity to a canonical ADP-ribose hydrolase and to a nucleoside diphosphate sugar hydrolase (1.4 and 1.3 Å Cα RMSD respectively). Examination of the structural elements conserved in both types of enzymes confirms that an aspartate-X-lysine motif on the C-terminal helix of the α-β-α NDPSase fold differentiates NDPSases from ADPRases.
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Affiliation(s)
- Andres H. de la Peña
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Allison Suarez
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Krisna C. Duong-ly
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Andrew J. Schoeffield
- Biology Department, Loyola University Maryland, Baltimore, Maryland, United States of America
| | - Mario A. Pizarro-Dupuy
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Melissa Zarr
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Silvia A. Pineiro
- Department of Medical and Research Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - L. Mario Amzel
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sandra B. Gabelli
- Structural Enzymology and Thermodynamics Group, Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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21
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Vasilyev N, Serganov A. Structures of RNA complexes with the Escherichia coli RNA pyrophosphohydrolase RppH unveil the basis for specific 5'-end-dependent mRNA decay. J Biol Chem 2015; 290:9487-99. [PMID: 25657011 DOI: 10.1074/jbc.m114.634824] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Indexed: 12/20/2022] Open
Abstract
5'-End-dependent RNA degradation impacts virulence, stress responses, and DNA repair in bacteria by controlling the decay of hundreds of mRNAs. The RNA pyrophosphohydrolase RppH, a member of the Nudix hydrolase superfamily, triggers this degradation pathway by removing pyrophosphate from the triphosphorylated RNA 5' terminus. Here, we report the x-ray structures of Escherichia coli RppH (EcRppH) in apo- and RNA-bound forms. These structures show distinct conformations of EcRppH·RNA complexes on the catalytic pathway and suggest a common catalytic mechanism for Nudix hydrolases. EcRppH interacts with RNA by a bipartite mechanism involving specific recognition of the 5'-terminal triphosphate and the second nucleotide, thus enabling discrimination against mononucleotides as substrates. The structures also reveal the molecular basis for the preference of the enzyme for RNA substrates bearing guanine in the second position by identifying a protein cleft in which guanine interacts with EcRppH side chains via cation-π contacts and hydrogen bonds. These interactions explain the modest specificity of EcRppH at the 5' terminus and distinguish the enzyme from the highly selective RppH present in Bacillus subtilis. The divergent means by which RNA is recognized by these two functionally and structurally analogous enzymes have important implications for mRNA decay and the regulation of protein biosynthesis in bacteria.
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Affiliation(s)
- Nikita Vasilyev
- From the Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016
| | - Alexander Serganov
- From the Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016
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22
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Foley PL, Hsieh PK, Luciano DJ, Belasco JG. Specificity and evolutionary conservation of the Escherichia coli RNA pyrophosphohydrolase RppH. J Biol Chem 2015; 290:9478-86. [PMID: 25657006 DOI: 10.1074/jbc.m114.634659] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Indexed: 12/20/2022] Open
Abstract
Bacterial RNA degradation often begins with conversion of the 5'-terminal triphosphate to a monophosphate by the RNA pyrophosphohydrolase RppH, an event that triggers rapid ribonucleolytic attack. Besides its role as the master regulator of 5'-end-dependent mRNA decay, RppH is important for the ability of pathogenic bacteria to invade host cells, yet little is known about how it chooses its targets. Here, we show that Escherichia coli RppH (EcRppH) requires at least two unpaired nucleotides at the RNA 5' end and prefers three or more such nucleotides. It can tolerate any nucleotide at the first three positions but has a modest preference for A at the 5' terminus and either a G or A at the second position. Mutational analysis has identified EcRppH residues crucial for substrate recognition or catalysis. The promiscuity of EcRppH differentiates it from its Bacillus subtilis counterpart, which has a strict RNA sequence requirement. EcRppH orthologs likely to share its relaxed sequence specificity are widespread in all classes of Proteobacteria, except Deltaproteobacteria, and in flowering plants. By contrast, the phylogenetic range of recognizable B. subtilis RppH orthologs appears to be restricted to the order Bacillales. These findings help to explain the selective influence of RppH on bacterial mRNA decay and show that RppH-dependent degradation has diversified significantly during the course of evolution.
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Affiliation(s)
- Patricia L Foley
- From the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Ping-kun Hsieh
- From the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Daniel J Luciano
- From the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
| | - Joel G Belasco
- From the Kimmel Center for Biology and Medicine at the Skirball Institute and the Department of Microbiology, New York University School of Medicine, New York, New York 10016
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Chapman EG, Moon SL, Wilusz J, Kieft JS. RNA structures that resist degradation by Xrn1 produce a pathogenic Dengue virus RNA. eLife 2014; 3:e01892. [PMID: 24692447 PMCID: PMC3968743 DOI: 10.7554/elife.01892] [Citation(s) in RCA: 149] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 02/25/2014] [Indexed: 12/16/2022] Open
Abstract
Dengue virus is a growing global health threat. Dengue and other flaviviruses commandeer the host cell's RNA degradation machinery to generate the small flaviviral RNA (sfRNA), a noncoding RNA that induces cytopathicity and pathogenesis. Host cell exonuclease Xrn1 likely loads on the 5' end of viral genomic RNA and degrades processively through ∼10 kB of RNA, halting near the 3' end of the viral RNA. The surviving RNA is the sfRNA. We interrogated the architecture of the complete Dengue 2 sfRNA, identifying five independently-folded RNA structures, two of which quantitatively confer Xrn1 resistance. We developed an assay for real-time monitoring of Xrn1 resistance that we used with mutagenesis and RNA folding experiments to show that Xrn1-resistant RNAs adopt a specific fold organized around a three-way junction. Disrupting the junction's fold eliminates the buildup of disease-related sfRNAs in human cells infected with a flavivirus, directly linking RNA structure to sfRNA production. DOI: http://dx.doi.org/10.7554/eLife.01892.001.
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Affiliation(s)
- Erich G Chapman
- Department of Biochemistry and Molecular Genetics, Howard Hughes Medical Institute, University of Colorado Denver School of Medicine, Aurora, United States
| | - Stephanie L Moon
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, United States
| | - Jeffrey Wilusz
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, United States
| | - Jeffrey S Kieft
- Department of Biochemistry and Molecular Genetics, Howard Hughes Medical Institute, University of Colorado Denver School of Medicine, Aurora, United States
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24
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Middleton CL, Parker JL, Knott GJ, White MF, Bond CS. Crystal ‘Unengineering’: Reducing the Crystallisability of Sulfolobus solfataricus Hjc. Aust J Chem 2014. [DOI: 10.1071/ch14342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The protein Hjc from the thermophilic archaeon Sulfolobus solfataricus (Ss) presented many challenges to both structure solution and formation of stable complexes with its substrate, the DNA four-way or Holliday junction. As the challenges were caused by an uncharacteristically high propensity for rapid and promiscuous crystallisation, we investigated the molecular cause of this behaviour, corrected it by mutagenesis, and solved the X-ray crystal structures of the two mutants. An active site mutant SsHjcA32A crystallised in space group I23 (a 144.2 Å; 68 % solvent), and a deletion of a key crystal contact site, SsHjcδ62–63 crystallised in space group P21 (a 64.60, b 61.83, c 55.25 Å; β = 95.74°; 28 % solvent). Characterisation and comparative analysis of the structures are presented along with discussion of the pitfalls of the use of protein engineering to alter crystallisability while maintaining biological function.
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25
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Piton J, Larue V, Thillier Y, Dorléans A, Pellegrini O, Li de la Sierra-Gallay I, Vasseur JJ, Debart F, Tisné C, Condon C. Bacillus subtilis RNA deprotection enzyme RppH recognizes guanosine in the second position of its substrates. Proc Natl Acad Sci U S A 2013; 110:8858-63. [PMID: 23610407 PMCID: PMC3670357 DOI: 10.1073/pnas.1221510110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The initiation of mRNA degradation often requires deprotection of its 5' end. In eukaryotes, the 5'-methylguanosine (cap) structure is principally removed by the Nudix family decapping enzyme Dcp2, yielding a 5'-monophosphorylated RNA that is a substrate for 5' exoribonucleases. In bacteria, the 5'-triphosphate group of primary transcripts is also converted to a 5' monophosphate by a Nudix protein called RNA pyrophosphohydrolase (RppH), allowing access to both endo- and 5' exoribonucleases. Here we present the crystal structures of Bacillus subtilis RppH (BsRppH) bound to GTP and to a triphosphorylated dinucleotide RNA. In contrast to Bdellovibrio bacteriovorus RppH, which recognizes the first nucleotide of its RNA targets, the B. subtilis enzyme has a binding pocket that prefers guanosine residues in the second position of its substrates. The identification of sequence specificity for RppH in an internal position was a highly unexpected result. NMR chemical shift mapping in solution shows that at least three nucleotides are required for unambiguous binding of RNA. Biochemical assays of BsRppH on RNA substrates with single-base-mutation changes in the first four nucleotides confirm the importance of guanosine in position two for optimal enzyme activity. Our experiments highlight important structural and functional differences between BsRppH and the RNA deprotection enzymes of distantly related bacteria.
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Affiliation(s)
- Jérémie Piton
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité) Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Valéry Larue
- Unité Mixte de Recherche (UMR) 8015, CNRS, Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; and
| | - Yann Thillier
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS–Université Montpellier 1–Université Montpellier 2, 34095 Montpellier Cedex 05, France
| | - Audrey Dorléans
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité) Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Olivier Pellegrini
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité) Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Inés Li de la Sierra-Gallay
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité) Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jean-Jacques Vasseur
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS–Université Montpellier 1–Université Montpellier 2, 34095 Montpellier Cedex 05, France
| | - Françoise Debart
- Institut des Biomolécules Max Mousseron, UMR 5247, CNRS–Université Montpellier 1–Université Montpellier 2, 34095 Montpellier Cedex 05, France
| | - Carine Tisné
- Unité Mixte de Recherche (UMR) 8015, CNRS, Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France; and
| | - Ciarán Condon
- Centre National de la Recherche Scientifique (CNRS), Unité Propre de Recherche 9073 (affiliated with Université Paris Diderot, Sorbonne Paris Cité) Institut de Biologie Physico-Chimique, 75005 Paris, France
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26
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Duong-Ly KC, Woo HN, Dunn CA, Xu W, Babič A, Bessman MJ, Amzel LM, Gabelli SB. A UDP-X diphosphatase from Streptococcus pneumoniae hydrolyzes precursors of peptidoglycan biosynthesis. PLoS One 2013; 8:e64241. [PMID: 23691178 PMCID: PMC3655063 DOI: 10.1371/journal.pone.0064241] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 03/29/2013] [Indexed: 01/09/2023] Open
Abstract
The gene for a Nudix enzyme (SP_1669) was found to code for a UDP-X diphosphatase. The SP_1669 gene is localized among genes encoding proteins that participate in cell division in Streptococcus pneumoniae. One of these genes, MurF, encodes an enzyme that catalyzes the last step of the Mur pathway of peptidoglycan biosynthesis. Mur pathway substrates are all derived from UDP-glucosamine and all are potential Nudix substrates. We showed that UDP-X diphosphatase can hydrolyze the Mur pathway substrates UDP-N-acetylmuramic acid and UDP-N-acetylmuramoyl-L-alanine. The 1.39 Å resolution crystal structure of this enzyme shows that it folds as an asymmetric homodimer with two distinct active sites, each containing elements of the conserved Nudix box sequence. In addition to its Nudix catalytic activity, the enzyme has a 3'5' RNA exonuclease activity. We propose that the structural asymmetry in UDP-X diphosphatase facilitates the recognition of these two distinct classes of substrates, Nudix substrates and RNA. UDP-X diphosphatase is a prototype of a new family of Nudix enzymes with unique structural characteristics: two monomers, each consisting of an N-terminal helix bundle domain and a C-terminal Nudix domain, form an asymmetric dimer with two distinct active sites. These enzymes function to hydrolyze bacterial cell wall precursors and degrade RNA.
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Affiliation(s)
- Krisna C. Duong-Ly
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Hyun Nyun Woo
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Christopher A. Dunn
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - WenLian Xu
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Andrej Babič
- School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Maurice J. Bessman
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - L. Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (LMA); (SBG)
| | - Sandra B. Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (LMA); (SBG)
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27
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Beringer DX, Kroon-Batenburg LMJ. The structure of the FnI-EGF-like tandem domain of coagulation factor XII solved using SIRAS. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:94-102. [PMID: 23385745 PMCID: PMC3564606 DOI: 10.1107/s1744309113000286] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 01/03/2013] [Indexed: 11/10/2022]
Abstract
Coagulation factor XII (FXII) is a key protein in the intrinsic coagulation and kallikrein-kinin pathways. It has been found that negative surfaces and amyloids, such as Aβ fibrils, can activate FXII. Additionally, it has been suggested that FXII simulates cells and that it plays an important role in thrombosis. To date, no structural data on FXII have been deposited, which makes it difficult to support any hypothesis on the mechanism of FXII function. The crystal structure of the FnI-EGF-like tandem domain of FXII presented here was solved using experimental phases. To determine the phases, a SIRAS approach was used with a native and a holmium chloride-soaked data set. The holmium cluster was coordinated by the C-terminal tails of two symmetry-related molecules. Another observation was that the FnI domain was much more ordered than the EGF-like domain owing to crystal packing. Furthermore, the structure shows the same domain orientation as the homologous FnI-EGF-like tandem domain of tPA. The plausibility of several proposed interactions of these domains of FXII is discussed. Based on this FXII FnI-EGF-like structure, it could be possible that FXII binding to amyloid and negatively charged surfaces is mediated via this part of FXII.
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Affiliation(s)
- D. X. Beringer
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
| | - L. M. J. Kroon-Batenburg
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Department of Chemistry, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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28
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McLennan AG. Substrate ambiguity among the nudix hydrolases: biologically significant, evolutionary remnant, or both? Cell Mol Life Sci 2013; 70:373-85. [PMID: 23184251 PMCID: PMC11113851 DOI: 10.1007/s00018-012-1210-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/01/2012] [Accepted: 11/05/2012] [Indexed: 12/20/2022]
Abstract
Many members of the nudix hydrolase family exhibit considerable substrate multispecificity and ambiguity, which raises significant issues when assessing their functions in vivo and gives rise to errors in database annotation. Several display low antimutator activity when expressed in bacterial tester strains as well as some degree of activity in vitro towards mutagenic, oxidized nucleotides such as 8-oxo-dGTP. However, many of these show greater activity towards other nucleotides such as ADP-ribose or diadenosine tetraphosphate (Ap(4)A). The antimutator activities have tended to gain prominence in the literature, whereas they may in fact represent the residual activity of an ancestral antimutator enzyme that has become secondary to the more recently evolved major activity after gene duplication. Whether any meaningful antimutagenic function has also been retained in vivo requires very careful assessment. Then again, other examples of substrate ambiguity may indicate as yet unexplored regulatory systems. For example, bacterial Ap(4)A hydrolases also efficiently remove pyrophosphate from the 5' termini of mRNAs, suggesting a potential role for Ap(4)A in the control of bacterial mRNA turnover, while the ability of some eukaryotic mRNA decapping enzymes to degrade IDP and dIDP or diphosphoinositol polyphosphates (DIPs) may also be indicative of new regulatory networks in RNA metabolism. DIP phosphohydrolases also degrade diadenosine polyphosphates and inorganic polyphosphates, suggesting further avenues for investigation. This article uses these and other examples to highlight the need for a greater awareness of the possible significance of substrate ambiguity among the nudix hydrolases as well as the need to exert caution when interpreting incomplete analyses.
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Affiliation(s)
- Alexander G McLennan
- Institute of Integrative Biology, University of Liverpool, Biosciences Building, Crown St., Liverpool, L69 7ZB, UK.
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29
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Smith BA, Jackman JE. Kinetic analysis of 3'-5' nucleotide addition catalyzed by eukaryotic tRNA(His) guanylyltransferase. Biochemistry 2011; 51:453-65. [PMID: 22136300 DOI: 10.1021/bi201397f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tRNA(His) guanylyltransferase (Thg1) catalyzes the incorporation of a single guanosine residue at the -1 position (G(-1)) of tRNA(His), using an unusual 3'-5' nucleotidyl transfer reaction. Thg1 and Thg1 orthologs known as Thg1-like proteins (TLPs), which catalyze tRNA repair and editing, are the only known enzymes that add nucleotides in the 3'-5' direction. Thg1 enzymes share no identifiable sequence similarity with any other known enzyme family that could be used to suggest the mechanism for catalysis of the unusual 3'-5' addition reaction. The high-resolution crystal structure of human Thg1 revealed remarkable structural similarity between canonical DNA/RNA polymerases and eukaryotic Thg1; nevertheless, questions regarding the molecular mechanism of 3'-5' nucleotide addition remain. Here, we use transient kinetics to measure the pseudo-first-order forward rate constants for the three steps of the G(-1) addition reaction catalyzed by yeast Thg1: adenylylation of the 5' end of the tRNA (k(aden)), nucleotidyl transfer (k(ntrans)), and removal of pyrophosphate from the G(-1)-containing tRNA (k(ppase)). This kinetic framework, in conjunction with the crystal structure of nucleotide-bound Thg1, suggests a likely role for two-metal ion chemistry in all three chemical steps of the G(-1) addition reaction. Furthermore, we have identified additional residues (K44 and N161) involved in adenylylation and three positively charged residues (R27, K96, and R133) that participate primarily in the nucleotidyl transfer step of the reaction. These data provide a foundation for understanding the mechanism of 3'-5' nucleotide addition in tRNA(His) maturation.
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Affiliation(s)
- Brian A Smith
- Department of Biochemistry, Center for RNA Biology and Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio 43210, United States
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30
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Anupama K, Leela JK, Gowrishankar J. Two pathways for RNase E action in Escherichia coli in vivo and bypass of its essentiality in mutants defective for Rho-dependent transcription termination. Mol Microbiol 2011; 82:1330-48. [PMID: 22026368 DOI: 10.1111/j.1365-2958.2011.07895.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The endonuclease RNase E of Escherichia coli is essential for viability, but deletion of its C-terminal half (CTH) is not lethal. RNase E preferentially acts on 5'-monophosphorylated RNA whose generation from primary transcripts is catalysed by RppH, but ΔRppH strains are viable. Here we show that the RNase E-ΔCTH ΔRppH combination is lethal, and that the lethality is suppressed by rho or nusG mutations impairing Rho-dependent transcription termination. Lethality was correlated with defects in bulk mRNA decay and tRNA processing, which were reversed by the rho suppressor. Lethality suppression was dependent on RNase H1 or the helicase UvsW of phage T4, both of which act to remove RNA-DNA hybrids (R-loops). The rho and nusG mutations also rescued inviability of a double alteration R169Q (that abolishes 5'-sensing) with ΔCTH in RNase E, as also that of conditional RNase E deficiency. We suggest that the ΔCTH alteration leads to loss of a second 5'-end-independent pathway of RNase E action. We further propose that an increased abundance of R-loops in the rho and nusG mutants, although ordinarily inimical to growth, contributes to rescue the lethality associated with loss of the two RNase E cleavage pathways by providing an alternative means of RNA degradation.
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Affiliation(s)
- K Anupama
- Laboratory of Bacterial Genetics, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500 001, India
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31
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Evguenieva-Hackenberg E, Klug G. New aspects of RNA processing in prokaryotes. Curr Opin Microbiol 2011; 14:587-92. [DOI: 10.1016/j.mib.2011.07.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 07/15/2011] [Accepted: 07/23/2011] [Indexed: 10/17/2022]
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32
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Duong-Ly KC, Gabelli SB, Xu W, Dunn CA, Schoeffield AJ, Bessman MJ, Amzel LM. The Nudix hydrolase CDP-chase, a CDP-choline pyrophosphatase, is an asymmetric dimer with two distinct enzymatic activities. J Bacteriol 2011; 193:3175-85. [PMID: 21531795 PMCID: PMC3133267 DOI: 10.1128/jb.00089-11] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 04/22/2011] [Indexed: 11/20/2022] Open
Abstract
A Nudix enzyme from Bacillus cereus (NCBI RefSeq accession no. NP_831800) catalyzes the hydrolysis of CDP-choline to produce CMP and phosphocholine. Here, we show that in addition, the enzyme has a 3'→5' RNA exonuclease activity. The structure of the free enzyme, determined to a 1.8-Å resolution, shows that the enzyme is an asymmetric dimer. Each monomer consists of two domains, an N-terminal helical domain and a C-terminal Nudix domain. The N-terminal domain is placed relative to the C-terminal domain such as to result in an overall asymmetric arrangement with two distinct catalytic sites: one with an "enclosed" Nudix pyrophosphatase site and the other with a more open, less-defined cavity. Residues that may be important for determining the asymmetry are conserved among a group of uncharacterized Nudix enzymes from Gram-positive bacteria. Our data support a model where CDP-choline hydrolysis is catalyzed by the enclosed Nudix site and RNA exonuclease activity is catalyzed by the open site. CDP-Chase is the first identified member of a novel Nudix family in which structural asymmetry has a profound effect on the recognition of substrates.
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Affiliation(s)
- Krisna C. Duong-Ly
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Sandra B. Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - WenLian Xu
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - Christopher A. Dunn
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | | | - Maurice J. Bessman
- Department of Biology and McCollum-Pratt Institute, Johns Hopkins University, Baltimore, Maryland 21218
| | - L. Mario Amzel
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
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Schlüter JP, Reinkensmeier J, Daschkey S, Evguenieva-Hackenberg E, Janssen S, Jänicke S, Becker JD, Giegerich R, Becker A. A genome-wide survey of sRNAs in the symbiotic nitrogen-fixing alpha-proteobacterium Sinorhizobium meliloti. BMC Genomics 2010; 11:245. [PMID: 20398411 PMCID: PMC2873474 DOI: 10.1186/1471-2164-11-245] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 04/17/2010] [Indexed: 12/03/2022] Open
Abstract
Background Small untranslated RNAs (sRNAs) are widespread regulators of gene expression in bacteria. This study reports on a comprehensive screen for sRNAs in the symbiotic nitrogen-fixing alpha-proteobacterium Sinorhizobium meliloti applying deep sequencing of cDNAs and microarray hybridizations. Results A total of 1,125 sRNA candidates that were classified as trans-encoded sRNAs (173), cis-encoded antisense sRNAs (117), mRNA leader transcripts (379), and sense sRNAs overlapping coding regions (456) were identified in a size range of 50 to 348 nucleotides. Among these were transcripts corresponding to 82 previously reported sRNA candidates. Enrichment for RNAs with primary 5'-ends prior to sequencing of cDNAs suggested transcriptional start sites corresponding to 466 predicted sRNA regions. The consensus σ70 promoter motif CTTGAC-N17-CTATAT was found upstream of 101 sRNA candidates. Expression patterns derived from microarray hybridizations provided further information on conditions of expression of a number of sRNA candidates. Furthermore, GenBank, EMBL, DDBJ, PDB, and Rfam databases were searched for homologs of the sRNA candidates identified in this study. Searching Rfam family models with over 1,000 sRNA candidates, re-discovered only those sequences from S. meliloti already known and stored in Rfam, whereas BLAST searches suggested a number of homologs in related alpha-proteobacteria. Conclusions The screening data suggests that in S. meliloti about 3% of the genes encode trans-encoded sRNAs and about 2% antisense transcripts. Thus, this first comprehensive screen for sRNAs applying deep sequencing in an alpha-proteobacterium shows that sRNAs also occur in high number in this group of bacteria.
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Affiliation(s)
- Jan-Philip Schlüter
- Institute of Biology III, Faculty of Biology, University of Freiburg, Freiburg, Germany
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Nakamura T, Meshitsuka S, Kitagawa S, Abe N, Yamada J, Ishino T, Nakano H, Tsuzuki T, Doi T, Kobayashi Y, Fujii S, Sekiguchi M, Yamagata Y. Structural and dynamic features of the MutT protein in the recognition of nucleotides with the mutagenic 8-oxoguanine base. J Biol Chem 2010; 285:444-52. [PMID: 19864691 PMCID: PMC2804192 DOI: 10.1074/jbc.m109.066373] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 10/14/2009] [Indexed: 11/06/2022] Open
Abstract
Escherichia coli MutT hydrolyzes 8-oxo-dGTP to 8-oxo-dGMP, an event that can prevent the misincorporation of 8-oxoguanine opposite adenine in DNA. Of the several enzymes that recognize 8-oxoguanine, MutT exhibits high substrate specificity for 8-oxoguanine nucleotides; however, the structural basis for this specificity is unknown. The crystal structures of MutT in the apo and holo forms and in the binary and ternary forms complexed with the product 8-oxo-dGMP and 8-oxo-dGMP plus Mn(2+), respectively, were determined. MutT strictly recognizes the overall conformation of 8-oxo-dGMP through a number of hydrogen bonds. This recognition mode revealed that 8-oxoguanine nucleotides are discriminated from guanine nucleotides by not only the hydrogen bond between the N7-H and Odelta (N119) atoms but also by the syn glycosidic conformation that 8-oxoguanine nucleotides prefer. Nevertheless, these discrimination factors cannot by themselves explain the roughly 34,000-fold difference between the affinity of MutT for 8-oxo-dGMP and dGMP. When the binary complex of MutT with 8-oxo-dGMP is compared with the ligand-free form, ordering and considerable movement of the flexible loops surrounding 8-oxo-dGMP in the binary complex are observed. These results indicate that MutT specifically recognizes 8-oxoguanine nucleotides by the ligand-induced conformational change.
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Affiliation(s)
- Teruya Nakamura
- From the Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973
| | - Sachiko Meshitsuka
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Seiju Kitagawa
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Nanase Abe
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Junichi Yamada
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Tetsuya Ishino
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Hiroaki Nakano
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Teruhisa Tsuzuki
- the Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582
| | - Takefumi Doi
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Yuji Kobayashi
- the Graduate School of Pharmaceutical Sciences, Osaka University, Suita 565-0871
| | - Satoshi Fujii
- the School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, and
| | | | - Yuriko Yamagata
- From the Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto 862-0973
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35
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The impact of non-coding RNAs: workshop on new functions of regulatory RNAs in pro- & eukaryotes. EMBO Rep 2009; 10:563-7. [PMID: 19465893 DOI: 10.1038/embor.2009.100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 04/20/2009] [Indexed: 11/08/2022] Open
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36
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Abstract
Messing et al. (2009) report the homodimeric structure of the Bdellovibrio bacteriovorus RppH pyrophosphohydrolase, which hydrolyzes the mRNA 5' triphosphate to initiate bacterial mRNA decay. These structures reveal insights into BdRppH substrate recognition and analogies to eukaryotic decapping enzymes.
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