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[PMID]:28637321
[Au] Autor:Shin BS; Katoh T; Gutierrez E; Kim JR; Suga H; Dever TE
[Ad] Endereço:Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
[Ti] Título:Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis.
[So] Source:Nucleic Acids Res;45(14):8392-8402, 2017 Aug 21.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline.
[Mh] Termos MeSH primário: Aminoácidos/metabolismo
Lisina/análogos & derivados
Biossíntese Peptídica
Fatores de Iniciação de Peptídeos/metabolismo
Poliaminas/metabolismo
Proteínas de Ligação a RNA/metabolismo
Proteínas de Saccharomyces cerevisiae/metabolismo
[Mh] Termos MeSH secundário: Sequência de Bases
Lisina/metabolismo
Conformação de Ácido Nucleico
Fatores de Iniciação de Peptídeos/química
Peptídeos/metabolismo
Prolina/análogos & derivados
Prolina/química
Prolina/metabolismo
RNA de Transferência de Fenilalanina/química
RNA de Transferência de Fenilalanina/metabolismo
RNA de Transferência de Prolina/química
RNA de Transferência de Prolina/metabolismo
Proteínas de Ligação a RNA/química
Ribossomos/metabolismo
Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/metabolismo
Proteínas de Saccharomyces cerevisiae/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Amino Acids); 0 (Peptide Initiation Factors); 0 (Peptides); 0 (Polyamines); 0 (RNA, Transfer, Phe); 0 (RNA, Transfer, Pro); 0 (RNA-Binding Proteins); 0 (Saccharomyces cerevisiae Proteins); 0 (eukaryotic translation initiation factor 5A); 25191-13-3 (polyproline); 3874VXF092 (hypusine); 9DLQ4CIU6V (Proline); K3Z4F929H6 (Lysine)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171023
[Lr] Data última revisão:
171023
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170623
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkx532


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[PMID]:27899648
[Au] Autor:Hoffman KS; Berg MD; Shilton BH; Brandl CJ; O'Donoghue P
[Ad] Endereço:Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada.
[Ti] Título:Genetic selection for mistranslation rescues a defective co-chaperone in yeast.
[So] Source:Nucleic Acids Res;45(6):3407-3421, 2017 Apr 07.
[Is] ISSN:1362-4962
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Despite the general requirement for translation fidelity, mistranslation can be an adaptive response. We selected spontaneous second site mutations that suppress the stress sensitivity caused by a Saccharomyces cerevisiae tti2 allele with a Leu to Pro mutation at residue 187, identifying a single nucleotide mutation at the same position (C70U) in four tRNAProUGG genes. Linkage analysis and suppression by SUF9G3:U70 expressed from a centromeric plasmid confirmed the causative nature of the suppressor mutation. Since the mutation incorporates the G3:U70 identity element for alanyl-tRNA synthetase into tRNAPro, we hypothesized that suppression results from mistranslation of Pro187 in Tti2L187P as Ala. A strain expressing Tti2L187A was not stress sensitive. In vitro, tRNAProUGG (C70U) was mis-aminoacylated with alanine by alanyl-tRNA synthetase, but was not a substrate for prolyl-tRNA synthetase. Mass spectrometry from protein expressed in vivo and a novel GFP reporter for mistranslation confirmed substitution of alanine for proline at a rate of ∼6%. Mistranslating cells expressing SUF9G3:U70 induce a partial heat shock response but grow nearly identically to wild-type. Introducing the same G3:U70 mutation in SUF2 (tRNAProAGG) suppressed a second tti2 allele (tti2L50P). We have thus identified a strategy that allows mistranslation to suppress deleterious missense Pro mutations in Tti2.
[Mh] Termos MeSH primário: Substituição de Aminoácidos
Chaperonas Moleculares/genética
Biossíntese de Proteínas
RNA de Transferência de Prolina/genética
Proteínas de Saccharomyces cerevisiae/genética
Saccharomyces cerevisiae/genética
Supressão Genética
[Mh] Termos MeSH secundário: Alelos
Íntrons
Chaperonas Moleculares/biossíntese
Proteínas de Saccharomyces cerevisiae/biossíntese
Seleção Genética
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Molecular Chaperones); 0 (RNA, Transfer, Pro); 0 (Saccharomyces cerevisiae Proteins); 0 (Tti2 protein, S cerevisiae)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170814
[Lr] Data última revisão:
170814
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161201
[St] Status:MEDLINE
[do] DOI:10.1093/nar/gkw1021


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[PMID]:27827794
[Au] Autor:Melnikov S; Mailliot J; Rigger L; Neuner S; Shin BS; Yusupova G; Dever TE; Micura R; Yusupov M
[Ad] Endereço:Institute of Genetics and Molecular and Cellular Biology CNRS UMR7104 INSERM UMR964, Illkirch, France.
[Ti] Título:Molecular insights into protein synthesis with proline residues.
[So] Source:EMBO Rep;17(12):1776-1784, 2016 Dec.
[Is] ISSN:1469-3178
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Proline is an amino acid with a unique cyclic structure that facilitates the folding of many proteins, but also impedes the rate of peptide bond formation by the ribosome. As a ribosome substrate, proline reacts markedly slower when compared with other amino acids both as a donor and as an acceptor of the nascent peptide. Furthermore, synthesis of peptides with consecutive proline residues triggers ribosome stalling. Here, we report crystal structures of the eukaryotic ribosome bound to analogs of mono- and diprolyl-tRNAs. These structures provide a high-resolution insight into unique properties of proline as a ribosome substrate. They show that the cyclic structure of proline residue prevents proline positioning in the amino acid binding pocket and affects the nascent peptide chain position in the ribosomal peptide exit tunnel. These observations extend current knowledge of the protein synthesis mechanism. They also revise an old dogma that amino acids bind the ribosomal active site in a uniform way by showing that proline has a binding mode distinct from other amino acids.
[Mh] Termos MeSH primário: Peptídeos/metabolismo
Prolina/metabolismo
Biossíntese de Proteínas
Ribossomos/química
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Cristalografia por Raios X
Escherichia coli/genética
Modelos Moleculares
Peptídeos/química
Prolina/química
Ligação Proteica
RNA de Transferência de Prolina/metabolismo
Ribossomos/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Peptides); 0 (RNA, Transfer, Pro); 9DLQ4CIU6V (Proline)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170922
[Lr] Data última revisão:
170922
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161110
[St] Status:MEDLINE


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[PMID]:27350030
[Au] Autor:Nam D; Choi E; Shin D; Lee EJ
[Ad] Endereço:Division of Microbiology, Department of Molecular Cell Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon, 16419, South Korea.
[Ti] Título:tRNA -mediated downregulation of elongation factor P is required for mgtCBR expression during Salmonella infection.
[So] Source:Mol Microbiol;102(2):221-232, 2016 Oct.
[Is] ISSN:1365-2958
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Bacterial ribosome requires elongation factor P to translate fragments harbouring consecutive proline codons. Given the abundance of ORFs with potential EF-P regulated sites, EF-P was assumed to be constitutively expressed. Here, we report that the intracellular pathogen Salmonella enterica serovar Typhimurium decreases efp mRNA levels during course of infection. We determined that the decrease in efp mRNA is triggered by low levels of charged tRNA , a condition that Salmonella experiences when inside a macrophage phagosome. Surprisingly, downregulation of EF-P selectively promotes expression of the virulence mgtC gene and contributes to Salmonella's ability to survive inside macrophages. The decrease in EF-P levels induces ribosome stalling at the consecutive proline codons of the mgtP open reading frame in the mgtCBR leader RNA, and thus allows formation of a stem-loop structure promoting transcription of the mgtC gene. The substitution of proline codons in the mgtP gene eliminates EF-P-mediated mgtC expression and thus Salmonella's survival inside macrophages. Our findings indicate that Salmonella benefits virulence genes by decreasing EF-P levels and inducing the stringent response inside host.
[Mh] Termos MeSH primário: Fatores de Alongamento de Peptídeos/metabolismo
RNA de Transferência de Prolina/metabolismo
Infecções por Salmonella/microbiologia
Salmonella typhimurium/metabolismo
[Mh] Termos MeSH secundário: Animais
Proteínas de Bactérias/metabolismo
Linhagem Celular
Regulação para Baixo
Regulação Bacteriana da Expressão Gênica
Inativação Gênica
Macrófagos/microbiologia
Camundongos
Fases de Leitura Aberta
Fatores de Alongamento de Peptídeos/genética
Fagossomos/metabolismo
RNA de Transferência de Prolina/genética
Ribossomos/metabolismo
Salmonella typhimurium/genética
Salmonella typhimurium/patogenicidade
Virulência
Fatores de Virulência/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (Peptide Elongation Factors); 0 (RNA, Transfer, Pro); 0 (Virulence Factors); 0 (factor EF-P)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170808
[Lr] Data última revisão:
170808
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160629
[St] Status:MEDLINE
[do] DOI:10.1111/mmi.13454


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[PMID]:26140378
[Au] Autor:Gamper HB; Masuda I; Frenkel-Morgenstern M; Hou YM
[Ad] Endereço:Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA. howard.gamper@jefferson.edu.
[Ti] Título:The UGG Isoacceptor of tRNAPro Is Naturally Prone to Frameshifts.
[So] Source:Int J Mol Sci;16(7):14866-83, 2015 Jul 01.
[Is] ISSN:1422-0067
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:Native tRNAs often contain post-transcriptional modifications to the wobble position to expand the capacity of reading the genetic code. Some of these modifications, due to the ability to confer imperfect codon-anticodon pairing at the wobble position, can induce a high propensity for tRNA to shift into alternative reading frames. An example is the native UGG isoacceptor of E. coli tRNAPro whose wobble nucleotide U34 is post-transcriptionally modified to cmo5U34 to read all four proline codons (5'-CCA, 5'-CCC, 5'-CCG, and 5'-CCU). Because the pairing of the modified anticodon to CCC codon is particularly weak relative to CCA and CCG codons, this tRNA can readily shift into both the +1 and +2-frame on the slippery mRNA sequence CCC-CG. We show that the shift to the +2-frame is more dominant, driven by the higher stability of the codon-anticodon pairing at the wobble position. Kinetic analysis suggests that both types of shifts can occur during stalling of the tRNA in a post-translocation complex or during translocation from the A to the P-site. Importantly, while the +1-frame post complex is active for peptidyl transfer, the +2-frame complex is a poor peptidyl donor. Together with our recent work, we draw a mechanistic distinction between +1 and +2-frameshifts, showing that while the +1-shifts are suppressed by the additional post-transcriptionally modified m1G37 nucleotide in the anticodon loop, the +2-shifts are suppressed by the ribosome, supporting a role of the ribosome in the overall quality control of reading-frame maintenance.
[Mh] Termos MeSH primário: Mutação da Fase de Leitura
RNA de Transferência de Prolina/genética
[Mh] Termos MeSH secundário: Pareamento de Bases
Códon/genética
Escherichia coli/genética
RNA Mensageiro/genética
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL
[Nm] Nome de substância:
0 (Codon); 0 (RNA, Messenger); 0 (RNA, Transfer, Pro)
[Em] Mês de entrada:1603
[Cu] Atualização por classe:161019
[Lr] Data última revisão:
161019
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:150704
[St] Status:MEDLINE
[do] DOI:10.3390/ijms160714866


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[PMID]:24676899
[Au] Autor:Liu J; Pampillo M; Guo F; Liu S; Cooperman BS; Farrell I; Dahary D; Gan BS; O'Gorman DB; Smilansky Z; Babwah AV; Leask A
[Ad] Endereço:Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada; Department of Burns and Cutaneous Surgery, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi, China.
[Ti] Título:Monitoring collagen synthesis in fibroblasts using fluorescently labeled tRNA pairs.
[So] Source:J Cell Physiol;229(9):1121-9, 2014 Sep.
[Is] ISSN:1097-4652
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:There is a critical need for techniques that directly monitor protein synthesis within cells isolated from normal and diseased tissue. Fibrotic disease, for which there is no drug treatment, is characterized by the overexpression of collagens. Here, we use a bioinformatics approach to identify a pair of glycine and proline isoacceptor tRNAs as being specific for the decoding of collagen mRNAs, leading to development of a FRET-based approach, dicodon monitoring of protein synthesis (DiCoMPS), that directly monitors the synthesis of collagen. DiCoMPS aimed at detecting collagen synthesis will be helpful in identifying novel anti-fibrotic compounds in cells derived from patients with fibrosis of any etiology, and, suitably adapted, should be widely applicable in monitoring the synthesis of other proteins in cells.
[Mh] Termos MeSH primário: Colágeno/biossíntese
Fibroblastos/metabolismo
Transferência Ressonante de Energia de Fluorescência
Microscopia Confocal
RNA de Transferência de Glicina/metabolismo
RNA de Transferência de Prolina/metabolismo
[Mh] Termos MeSH secundário: Animais
Carbocianinas/metabolismo
Células Cultivadas
Fibroblastos/patologia
Fibrose
Corantes Fluorescentes/metabolismo
Seres Humanos
Cinética
Camundongos
Camundongos Knockout
PTEN Fosfo-Hidrolase/deficiência
PTEN Fosfo-Hidrolase/genética
RNA de Transferência de Glicina/genética
RNA de Transferência de Prolina/genética
Transfecção
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Carbocyanines); 0 (Fluorescent Dyes); 0 (RNA, Transfer, Gly); 0 (RNA, Transfer, Pro); 0 (cyanine dye 3); 0 (cyanine dye 5); 9007-34-5 (Collagen); EC 3.1.3.67 (PTEN Phosphohydrolase); EC 3.1.3.67 (Pten protein, mouse)
[Em] Mês de entrada:1407
[Cu] Atualização por classe:161125
[Lr] Data última revisão:
161125
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140329
[St] Status:MEDLINE
[do] DOI:10.1002/jcp.24630


  7 / 189 MEDLINE  
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[PMID]:24673854
[Au] Autor:Wang J; Kwiatkowski M; Pavlov MY; Ehrenberg M; Forster AC
[Ad] Endereço:Department of Cell and Molecular Biology, Uppsala University , Husargatan 3, Box 596, Uppsala 75124, Sweden.
[Ti] Título:Peptide formation by N-methyl amino acids in translation is hastened by higher pH and tRNA(Pro).
[So] Source:ACS Chem Biol;9(6):1303-11, 2014 Jun 20.
[Is] ISSN:1554-8937
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Applications of N-methyl amino acids (NMAAs) in drug discovery are limited by their low efficiencies of ribosomal incorporation, and little is known mechanistically about the steps leading to incorporation. Here, we demonstrate that a synthetic tRNA body based on a natural N-alkyl amino acid carrier, tRNA(Pro), increases translation incorporation rates of all three studied NMAAs compared with tRNA(Phe)- and tRNA(Ala)-based bodies. We also investigate the pH dependence of the incorporation rates and find that the rates increase dramatically in the range of pH 7 to 8.5 with the titration of a single proton. Results support a rate-limiting peptidyl transfer step dependent on deprotonation of the N-nucleophile of the NMAA. Competition experiments demonstrate that several futile cycles of delivery and rejection of A-site NMAA-tRNA are required per peptide bond formed and that increasing magnesium ion concentration increases incorporation yield. Data clarify the mechanism of ribosomal NMAA incorporation and provide three generalizable ways to improve incorporation of NMAAs in translation.
[Mh] Termos MeSH primário: Aminoácidos/metabolismo
Escherichia coli/metabolismo
Biossíntese Peptídica/fisiologia
RNA Mensageiro/genética
RNA de Transferência de Prolina/metabolismo
Ribossomos/metabolismo
[Mh] Termos MeSH secundário: Escherichia coli/genética
Concentração de Íons de Hidrogênio
Cinética
Modelos Biológicos
Estrutura Molecular
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Amino Acids); 0 (RNA, Messenger); 0 (RNA, Transfer, Pro)
[Em] Mês de entrada:1508
[Cu] Atualização por classe:140814
[Lr] Data última revisão:
140814
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140329
[St] Status:MEDLINE
[do] DOI:10.1021/cb500036a


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[PMID]:24587376
[Au] Autor:Bergman JM; Hammarlöf DL; Hughes D
[Ad] Endereço:Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
[Ti] Título:Reducing ppGpp level rescues an extreme growth defect caused by mutant EF-Tu.
[So] Source:PLoS One;9(2):e90486, 2014.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Transcription and translation of mRNA's are coordinated processes in bacteria. We have previously shown that a mutant form of EF-Tu (Gln125Arg) in Salmonella Typhimurium with a reduced affinity for aa-tRNA, causes ribosome pausing, resulting in an increased rate of RNase E-mediated mRNA cleavage, causing extremely slow growth, even on rich medium. The slow growth phenotype is reversed by mutations that reduce RNase E activity. Here we asked whether the slow growth phenotype could be reversed by overexpression of a wild-type gene. We identified spoT (encoding ppGpp synthetase/hydrolase) as a gene that partially reversed the slow growth rate when overexpressed. We found that the slow-growing mutant had an abnormally high basal level of ppGpp that was reduced when spoT was overexpressed. Inactivating relA (encoding the ribosome-associated ppGpp synthetase) also reduced ppGpp levels and significantly increased growth rate. Because RelA responds specifically to deacylated tRNA in the ribosomal A-site this suggested that the tuf mutant had an increased level of deacylated tRNA relative to the wild-type. To test this hypothesis we measured the relative acylation levels of 4 families of tRNAs and found that proline isoacceptors were acylated at a lower level in the mutant strain relative to the wild-type. In addition, the level of the proS tRNA synthetase mRNA was significantly lower in the mutant strain. We suggest that an increased level of deacylated tRNA in the mutant strain stimulates RelA-mediated ppGpp production, causing changes in transcription pattern that are inappropriate for rich media conditions, and contributing to slow growth rate. Reducing ppGpp levels, by altering the activity of either SpoT or RelA, removes one cause of the slow growth and reveals the interconnectedness of intracellular regulatory mechanisms.
[Mh] Termos MeSH primário: Proteínas de Bactérias/metabolismo
Guanosina Tetrafosfato/metabolismo
Ligases/metabolismo
Fator Tu de Elongação de Peptídeos/metabolismo
Pirofosfatases/metabolismo
[Mh] Termos MeSH secundário: Proteínas de Bactérias/genética
Cromatografia em Camada Delgada
Endorribonucleases/genética
Endorribonucleases/metabolismo
Regulação Bacteriana da Expressão Gênica
Genótipo
Ligases/genética
Mutação de Sentido Incorreto
Fator Tu de Elongação de Peptídeos/genética
Fenótipo
Pirofosfatases/genética
RNA Bacteriano/genética
RNA Bacteriano/metabolismo
RNA Ribossômico 16S/genética
RNA Ribossômico 16S/metabolismo
RNA de Transferência de Prolina/genética
RNA de Transferência de Prolina/metabolismo
Salmonella typhimurium/genética
Salmonella typhimurium/crescimento & desenvolvimento
Salmonella typhimurium/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (Bacterial Proteins); 0 (RNA, Bacterial); 0 (RNA, Ribosomal, 16S); 0 (RNA, Transfer, Pro); 33503-72-9 (Guanosine Tetraphosphate); EC 3.1.- (Endoribonucleases); EC 3.1.4.- (ribonuclease E); EC 3.1.7.2 (guanosine-3',5'-bis(diphosphate) 3'-pyrophosphatase); EC 3.6.1.- (Peptide Elongation Factor Tu); EC 3.6.1.- (Pyrophosphatases); EC 6.- (Ligases); EC 6.- (guanosine 3',5'-polyphosphate synthetases)
[Em] Mês de entrada:1506
[Cu] Atualização por classe:140303
[Lr] Data última revisão:
140303
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140304
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0090486


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[PMID]:24516160
[Au] Autor:Lee EJ; Choi J; Groisman EA
[Ad] Endereço:Howard Hughes Medical Institute and Department of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, CT 06536-0812.
[Ti] Título:Control of a Salmonella virulence operon by proline-charged tRNA(Pro).
[So] Source:Proc Natl Acad Sci U S A;111(8):3140-5, 2014 Feb 25.
[Is] ISSN:1091-6490
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:The intracellular pathogen Salmonella enterica serovar Typhimurium requires the mgtC gene to cause disease. The mgtC transcript includes a long leader region that harbors a short proline codon-rich ORF--termed mgtP--the translation of which is predicted to favor formation of one of two alternative stem-loop structures. We now report that the mgtP proline codons are critical for expression of the mgtC coding region inside host cells, for Salmonella survival inside macrophages, and for virulence in mice. We determine that the mgtP proline codons mediate the response to proline-charged tRNA(Pro), the levels of which decrease under proline limitation and/or hyperosmotic stress. The host compartment harboring Salmonella appears to be limited in proline because proline auxotrophs were defective for intramacrophage survival and virulence in mice. Salmonella seems to experience hyperosmotic stress during infection because osmotically regulated genes were highly induced inside phagocytic cells. Replacing mgtP proline codons with codons specifying threonine converted the mgtC leader into a threonine-responding element. Our findings indicate that an attenuation-like mechanism governs transcription elongation into the mgtCBR coding region. Moreover, they highlight how pathogens construe host signals by the effect they have on bacterial constituents.
[Mh] Termos MeSH primário: Regiões 5´ não Traduzidas/genética
Proteínas de Bactérias/genética
Proteínas de Transporte de Cátions/genética
Regulação Bacteriana da Expressão Gênica/genética
Interações Hospedeiro-Patógeno/genética
RNA de Transferência de Prolina/metabolismo
Salmonella typhimurium/patogenicidade
[Mh] Termos MeSH secundário: Sequência de Aminoácidos
Animais
Pareamento de Bases
Sequência de Bases
Códon/genética
Camundongos
Dados de Sequência Molecular
Oligodesoxirribonucleotídeos/genética
Fases de Leitura Aberta/genética
Prolina/genética
Prolina/metabolismo
RNA de Transferência de Prolina/genética
Reação em Cadeia da Polimerase em Tempo Real
Virulência
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (5' Untranslated Regions); 0 (Bacterial Proteins); 0 (Cation Transport Proteins); 0 (Codon); 0 (Oligodeoxyribonucleotides); 0 (RNA, Transfer, Pro); 9DLQ4CIU6V (Proline); EC 3.6.1.- (MgtC protein, Salmonella typhimurium)
[Em] Mês de entrada:1404
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140212
[St] Status:MEDLINE
[do] DOI:10.1073/pnas.1316209111


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[PMID]:24450765
[Au] Autor:Bartholow TG; Sanford BL; Cao B; Schmit HL; Johnson JM; Meitzner J; Bhattacharyya S; Musier-Forsyth K; Hati S
[Ad] Endereço:Department of Chemistry, University of Wisconsin-Eau Claire , Eau Claire, Wisconsin, 54702, United States.
[Ti] Título:Strictly conserved lysine of prolyl-tRNA Synthetase editing domain facilitates binding and positioning of misacylated tRNA(Pro.).
[So] Source:Biochemistry;53(6):1059-68, 2014 Feb 18.
[Is] ISSN:1520-4995
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:To ensure high fidelity in translation, many aminoacyl-tRNA synthetases, enzymes responsible for attaching specific amino acids to cognate tRNAs, require proof-reading mechanisms. Most bacterial prolyl-tRNA synthetases (ProRSs) misactivate alanine and employ a post-transfer editing mechanism to hydrolyze Ala-tRNA(Pro). This reaction occurs in a second catalytic site (INS) that is distinct from the synthetic active site. The 2'-OH of misacylated tRNA(Pro) and several conserved residues in the Escherichia coli ProRS INS domain are directly involved in Ala-tRNA(Pro) deacylation. Although mutation of the strictly conserved lysine 279 (K279) results in nearly complete loss of post-transfer editing activity, this residue does not directly participate in Ala-tRNA(Pro) hydrolysis. We hypothesized that the role of K279 is to bind the phosphate backbone of the acceptor stem of misacylated tRNA(Pro) and position it in the editing active site. To test this hypothesis, we carried out pKa, charge neutralization, and free-energy of binding calculations. Site-directed mutagenesis and kinetic studies were performed to verify the computational results. The calculations revealed a considerably higher pKa of K279 compared to an isolated lysine and showed that the protonated state of K279 is stabilized by the neighboring acidic residue. However, substitution of this acidic residue with a positively charged residue leads to a significant increase in Ala-tRNA(Pro) hydrolysis, suggesting that enhancement in positive charge density in the vicinity of K279 favors tRNA binding. A charge-swapping experiment and free energy of binding calculations support the conclusion that the positive charge at position 279 is absolutely necessary for tRNA binding in the editing active site.
[Mh] Termos MeSH primário: Aminoacil-tRNA Sintetases/metabolismo
Lisina/genética
[Mh] Termos MeSH secundário: Aminoacil-tRNA Sintetases/química
Domínio Catalítico
Simulação por Computador
Lisina/química
Lisina/metabolismo
Modelos Moleculares
Estrutura Terciária de Proteína
Edição de RNA
RNA de Transferência de Prolina/metabolismo
Termodinâmica
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, N.I.H., EXTRAMURAL; RESEARCH SUPPORT, NON-U.S. GOV'T
[Nm] Nome de substância:
0 (RNA, Transfer, Pro); 0 (alanyl-tRNA(Pro)); EC 6.1.1.- (Amino Acyl-tRNA Synthetases); EC 6.1.1.15 (prolyl T RNA synthetase); K3Z4F929H6 (Lysine)
[Em] Mês de entrada:1404
[Cu] Atualização por classe:170220
[Lr] Data última revisão:
170220
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:140124
[St] Status:MEDLINE
[do] DOI:10.1021/bi401279r



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