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In vivo proteomics identifies the competence regulon and AliB oligopeptide transporter as pathogenic factors in pneumococcal meningitis. PLoS Pathog 2019; 15:e1007987. [PMID: 31356624 PMCID: PMC6687184 DOI: 10.1371/journal.ppat.1007987] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 08/08/2019] [Accepted: 07/15/2019] [Indexed: 01/09/2023] Open
Abstract
Streptococcus pneumoniae (pneumococci) is a leading cause of severe bacterial meningitis in many countries worldwide. To characterize the repertoire of fitness and virulence factors predominantly expressed during meningitis we performed niche-specific analysis of the in vivo proteome in a mouse meningitis model, in which bacteria are directly inoculated into the cerebrospinal fluid (CSF) cisterna magna. We generated a comprehensive mass spectrometry (MS) spectra library enabling bacterial proteome analysis even in the presence of eukaryotic proteins. We recovered 200,000 pneumococci from CSF obtained from meningitis mice and by MS we identified 685 pneumococci proteins in samples from in vitro filter controls and 249 in CSF isolates. Strikingly, the regulatory two-component system ComDE and substrate-binding protein AliB of the oligopeptide transporter system were exclusively detected in pneumococci recovered from the CSF. In the mouse meningitis model, AliB-, ComDE-, or AliB-ComDE-deficiency resulted in attenuated meningeal inflammation and disease severity when compared to wild-type pneumococci indicating the crucial role of ComDE and AliB in pneumococcal meningitis. In conclusion, we show here mechanisms of pneumococcal adaptation to a defined host compartment by a proteome-based approach. Further, this study provides the basis of a promising strategy for the identification of protein antigens critical for invasive disease caused by pneumococci and other meningeal pathogens. Pneumococci are one of the most common and aggressive meningitis pathogens associated with mortality rates between 10% and 30%. Due to severe complications during therapeutic intervention, prevention strategies to combat pneumococcal meningitis (PM) are preferred. The vaccines available are so far suboptimal and inefficient to prevent serious PM. Hence, deciphering the mechanisms employed by pneumococci to encounter and survive in the cerebrospinal fluid (CSF) will pave the way for the development of new antimicrobial strategies. This work used an in vivo proteome-based approach to identify pneumococcal proteins expressed in the CSF during acute meningitis. This strategy identified a nutrient uptake system and regulatory system to be highly expressed in the CSF and being crucial for PM. Knocking out two of the highly in vivo expressed proteins (AliA and ComDE) in S. pneumoniae yields to a significant increase in survival and decrease in pathogen burden of infected mice. These host compartment specific expressed pneumococcal antigens represent promising candidates for antimicrobials or protein-based vaccines.
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A chiral selectivity relaxed paralog of DTD for proofreading tRNA mischarging in Animalia. Nat Commun 2018; 9:511. [PMID: 29410408 PMCID: PMC5802732 DOI: 10.1038/s41467-017-02204-w] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 11/13/2017] [Indexed: 01/07/2023] Open
Abstract
D-aminoacyl-tRNA deacylase (DTD), a bacterial/eukaryotic trans-editing factor, removes D-amino acids mischarged on tRNAs and achiral glycine mischarged on tRNAAla. An invariant cross-subunit Gly-cisPro motif forms the mechanistic basis of L-amino acid rejection from the catalytic site. Here, we present the identification of a DTD variant, named ATD (Animalia-specific tRNA deacylase), that harbors a Gly-transPro motif. The cis-to-trans switch causes a "gain of function" through L-chiral selectivity in ATD resulting in the clearing of L-alanine mischarged on tRNAThr(G4•U69) by eukaryotic AlaRS. The proofreading activity of ATD is conserved across diverse classes of phylum Chordata. Animalia genomes enriched in tRNAThr(G4•U69) genes are in strict association with the presence of ATD, underlining the mandatory requirement of a dedicated factor to proofread tRNA misaminoacylation. The study highlights the emergence of ATD during genome expansion as a key event associated with the evolution of Animalia.
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Kermgard E, Yang Z, Michel AM, Simari R, Wong J, Ibba M, Lazazzera BA. Quality Control by Isoleucyl-tRNA Synthetase of Bacillus subtilis Is Required for Efficient Sporulation. Sci Rep 2017; 7:41763. [PMID: 28139725 PMCID: PMC5282499 DOI: 10.1038/srep41763] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/22/2016] [Indexed: 11/11/2022] Open
Abstract
Isoleucyl-tRNA synthetase (IleRS) is an aminoacyl-tRNA synthetase whose essential function is to aminoacylate tRNAIle with isoleucine. Like some other aminoacyl-tRNA synthetases, IleRS can mischarge tRNAIle and correct this misacylation through a separate post-transfer editing function. To explore the biological significance of this editing function, we created a ileS(T233P) mutant of Bacillus subtilis that allows tRNAIle mischarging while retaining wild-type Ile-tRNAIle synthesis activity. As seen in other species defective for aminoacylation quality control, the growth rate of the ileS(T233P) strain was not significantly different from wild-type. When the ileS(T233P) strain was assessed for its ability to promote distinct phenotypes in response to starvation, the ileS(T233P) strain was observed to exhibit a significant defect in formation of environmentally resistant spores. The sporulation defect ranged from 3-fold to 30-fold and was due to a delay in activation of early sporulation genes. The loss of aminoacylation quality control in the ileS(T233P) strain resulted in the inability to compete with a wild-type strain under selective conditions that required sporulation. These data show that the quality control function of IleRS is required in B. subtilis for efficient sporulation and suggests that editing by aminoacyl-tRNA synthetases may be important for survival under starvation/nutrient limitation conditions.
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Affiliation(s)
- Elizabeth Kermgard
- Department of Microbiology, Immunology and Molecular Genetics University of California, Los Angeles, California 90095, USA
| | - Zhou Yang
- Department of Microbiology, Immunology and Molecular Genetics University of California, Los Angeles, California 90095, USA
| | - Annika-Marisa Michel
- Department of Microbiology, Immunology and Molecular Genetics University of California, Los Angeles, California 90095, USA.,Technische Universität Braunschweig, Institut of Microbiology, Braunschweig, Germany
| | - Rachel Simari
- Ohio State Biochemistry Program, Ohio State University, Columbus, Ohio 43210, USA
| | - Jacqueline Wong
- Department of Microbiology, Immunology and Molecular Genetics University of California, Los Angeles, California 90095, USA
| | - Michael Ibba
- Ohio State Biochemistry Program, Ohio State University, Columbus, Ohio 43210, USA.,Department of Microbiology, Ohio State University, Columbus, Ohio 43210, USA.,Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
| | - Beth A Lazazzera
- Department of Microbiology, Immunology and Molecular Genetics University of California, Los Angeles, California 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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Carter CW. Coding of Class I and II Aminoacyl-tRNA Synthetases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 966:103-148. [PMID: 28828732 PMCID: PMC5927602 DOI: 10.1007/5584_2017_93] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aminoacyl-tRNA synthetases and their cognate transfer RNAs translate the universal genetic code. The twenty canonical amino acids are sufficiently diverse to create a selective advantage for dividing amino acid activation between two distinct, apparently unrelated superfamilies of synthetases, Class I amino acids being generally larger and less polar, Class II amino acids smaller and more polar. Biochemical, bioinformatic, and protein engineering experiments support the hypothesis that the two Classes descended from opposite strands of the same ancestral gene. Parallel experimental deconstructions of Class I and II synthetases reveal parallel losses in catalytic proficiency at two novel modular levels-protozymes and Urzymes-associated with the evolution of catalytic activity. Bi-directional coding supports an important unification of the proteome; affords a genetic relatedness metric-middle base-pairing frequencies in sense/antisense alignments-that probes more deeply into the evolutionary history of translation than do single multiple sequence alignments; and has facilitated the analysis of hitherto unknown coding relationships in tRNA sequences. Reconstruction of native synthetases by modular thermodynamic cycles facilitated by domain engineering emphasizes the subtlety associated with achieving high specificity, shedding new light on allosteric relationships in contemporary synthetases. Synthetase Urzyme structural biology suggests that they are catalytically-active molten globules, broadening the potential manifold of polypeptide catalysts accessible to primitive genetic coding and motivating revisions of the origins of catalysis. Finally, bi-directional genetic coding of some of the oldest genes in the proteome places major limitations on the likelihood that any RNA World preceded the origins of coded proteins.
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Affiliation(s)
- Charles W Carter
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599-7260, USA.
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Translation quality control is critical for bacterial responses to amino acid stress. Proc Natl Acad Sci U S A 2016; 113:2252-7. [PMID: 26858451 DOI: 10.1073/pnas.1525206113] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Gene expression relies on quality control for accurate transmission of genetic information. One mechanism that prevents amino acid misincorporation errors during translation is editing of misacylated tRNAs by aminoacyl-tRNA synthetases. In the absence of editing, growth is limited upon exposure to excess noncognate amino acid substrates and other stresses, but whether these physiological effects result solely from mistranslation remains unclear. To explore if translation quality control influences cellular processes other than protein synthesis, an Escherichia coli strain defective in Tyr-tRNA(Phe) editing was used. In the absence of editing, cellular levels of aminoacylated tRNA(Phe) were elevated during amino acid stress, whereas in the wild-type strain these levels declined under the same growth conditions. In the editing-defective strain, increased levels of aminoacylated tRNA(Phe) led to continued synthesis of the PheL leader peptide and attenuation of pheA transcription under amino acid stress. Consequently, in the absence of editing, activation of the phenylalanine biosynthetic operon becomes less responsive to phenylalanine limitation. In addition to raising aminoacylated tRNA levels, the absence of editing lowered the amount of deacylated tRNA(Phe) in the cell. This reduction in deacylated tRNA was accompanied by decreased synthesis of the second messenger guanosine tetraphosphate and limited induction of stringent response-dependent gene expression in editing-defective cells during amino acid stress. These data show that a single quality-control mechanism, the editing of misacylated aminoacyl-tRNAs, provides a critical checkpoint both for maintaining the accuracy of translation and for determining the sensitivity of transcriptional responses to amino acid stress.
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Thiaville PC, El Yacoubi B, Köhrer C, Thiaville JJ, Deutsch C, Iwata-Reuyl D, Bacusmo JM, Armengaud J, Bessho Y, Wetzel C, Cao X, Limbach PA, RajBhandary UL, de Crécy-Lagard V. Essentiality of threonylcarbamoyladenosine (t(6)A), a universal tRNA modification, in bacteria. Mol Microbiol 2015; 98:1199-221. [PMID: 26337258 DOI: 10.1111/mmi.13209] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2015] [Indexed: 02/06/2023]
Abstract
Threonylcarbamoyladenosine (t(6)A) is a modified nucleoside universally conserved in tRNAs in all three kingdoms of life. The recently discovered genes for t(6)A synthesis, including tsaC and tsaD, are essential in model prokaryotes but not essential in yeast. These genes had been identified as antibacterial targets even before their functions were known. However, the molecular basis for this prokaryotic-specific essentiality has remained a mystery. Here, we show that t(6)A is a strong positive determinant for aminoacylation of tRNA by bacterial-type but not by eukaryotic-type isoleucyl-tRNA synthetases and might also be a determinant for the essential enzyme tRNA(Ile)-lysidine synthetase. We confirm that t(6)A is essential in Escherichia coli and a survey of genome-wide essentiality studies shows that genes for t(6)A synthesis are essential in most prokaryotes. This essentiality phenotype is not universal in Bacteria as t(6)A is dispensable in Deinococcus radiodurans, Thermus thermophilus, Synechocystis PCC6803 and Streptococcus mutans. Proteomic analysis of t(6)A(-) D. radiodurans strains revealed an induction of the proteotoxic stress response and identified genes whose translation is most affected by the absence of t(6)A in tRNAs. Thus, although t(6)A is universally conserved in tRNAs, its role in translation might vary greatly between organisms.
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Affiliation(s)
- Patrick C Thiaville
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.,Genetics and Genomics Graduate Program, University of Florida, Gainesville, FL, 32610, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.,Institut de Génétique et Microbiologie, Université of Paris-Sud, Orsay, France
| | - Basma El Yacoubi
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Caroline Köhrer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Jennifer J Thiaville
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Chris Deutsch
- Department of Chemistry, Portland State University, Portland, OR, 97297, USA
| | - Dirk Iwata-Reuyl
- Department of Chemistry, Portland State University, Portland, OR, 97297, USA
| | - Jo Marie Bacusmo
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA
| | - Jean Armengaud
- CEA, DSV, IBiTec-S, SPI, Li2D, Laboratory 'Innovative technologies for Detection and Diagnostics', Bagnols-sur-Cèze, F-30200, France
| | - Yoshitaka Bessho
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan.,Institute of Physics, Academia Sinica, 128 Sec. 2, Academia Rd., Nankang, Taipei, 11529, Taiwan
| | - Collin Wetzel
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Xiaoyu Cao
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Patrick A Limbach
- Rieveschl Laboratories for Mass Spectrometry, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, 45221, USA
| | - Uttam L RajBhandary
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL, 32611, USA.,University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32610, USA
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Shepherd J, Ibba M. Bacterial transfer RNAs. FEMS Microbiol Rev 2015; 39:280-300. [PMID: 25796611 DOI: 10.1093/femsre/fuv004] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/21/2015] [Indexed: 11/14/2022] Open
Abstract
Transfer RNA is an essential adapter molecule that is found across all three domains of life. The primary role of transfer RNA resides in its critical involvement in the accurate translation of messenger RNA codons during protein synthesis and, therefore, ultimately in the determination of cellular gene expression. This review aims to bring together the results of intensive investigations into the synthesis, maturation, modification, aminoacylation, editing and recycling of bacterial transfer RNAs. Codon recognition at the ribosome as well as the ever-increasing number of alternative roles for transfer RNA outside of translation will be discussed in the specific context of bacterial cells.
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Affiliation(s)
- Jennifer Shepherd
- Department of Microbiology and the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
| | - Michael Ibba
- Department of Microbiology and the Center for RNA Biology, Ohio State University, Columbus, Ohio 43210, USA
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