1
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Dimitrova-Paternoga L, Kasvandik S, Beckert B, Granneman S, Tenson T, Wilson DN, Paternoga H. Structural basis of ribosomal 30S subunit degradation by RNase R. Nature 2024; 626:1133-1140. [PMID: 38326618 PMCID: PMC10901742 DOI: 10.1038/s41586-024-07027-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 01/04/2024] [Indexed: 02/09/2024]
Abstract
Protein synthesis is a major energy-consuming process of the cell that requires the controlled production1-3 and turnover4,5 of ribosomes. Although the past few years have seen major advances in our understanding of ribosome biogenesis, structural insight into the degradation of ribosomes has been lacking. Here we present native structures of two distinct small ribosomal 30S subunit degradation intermediates associated with the 3' to 5' exonuclease ribonuclease R (RNase R). The structures reveal that RNase R binds at first to the 30S platform to facilitate the degradation of the functionally important anti-Shine-Dalgarno sequence and the decoding-site helix 44. RNase R then encounters a roadblock when it reaches the neck region of the 30S subunit, and this is overcome by a major structural rearrangement of the 30S head, involving the loss of ribosomal proteins. RNase R parallels this movement and relocates to the decoding site by using its N-terminal helix-turn-helix domain as an anchor. In vitro degradation assays suggest that head rearrangement poses a major kinetic barrier for RNase R, but also indicate that the enzyme alone is sufficient for complete degradation of 30S subunits. Collectively, our results provide a mechanistic basis for the degradation of 30S mediated by RNase R, and reveal that RNase R targets orphaned 30S subunits using a dynamic mechanism involving an anchored switching of binding sites.
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Affiliation(s)
| | - Sergo Kasvandik
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Bertrand Beckert
- Dubochet Center for Imaging (DCI) at EPFL, EPFL SB IPHYS DCI, Lausanne, Switzerland
| | - Sander Granneman
- Centre for Engineering Biology (SynthSys), University of Edinburgh, Edinburgh, UK
| | - Tanel Tenson
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Daniel N Wilson
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
| | - Helge Paternoga
- Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
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2
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Kumar N, Sharma S, Kaushal PS. Cryo- EM structure of the mycobacterial 70S ribosome in complex with ribosome hibernation promotion factor RafH. Nat Commun 2024; 15:638. [PMID: 38245551 PMCID: PMC10799931 DOI: 10.1038/s41467-024-44879-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 01/04/2024] [Indexed: 01/22/2024] Open
Abstract
Ribosome hibernation is a key survival strategy bacteria adopt under environmental stress, where a protein, hibernation promotion factor (HPF), transitorily inactivates the ribosome. Mycobacterium tuberculosis encounters hypoxia (low oxygen) as a major stress in the host macrophages, and upregulates the expression of RafH protein, which is crucial for its survival. The RafH, a dual domain HPF, an orthologue of bacterial long HPF (HPFlong), hibernates ribosome in 70S monosome form, whereas in other bacteria, the HPFlong induces 70S ribosome dimerization and hibernates its ribosome in 100S disome form. Here, we report the cryo- EM structure of M. smegmatis, a close homolog of M. tuberculosis, 70S ribosome in complex with the RafH factor at an overall 2.8 Å resolution. The N- terminus domain (NTD) of RafH binds to the decoding center, similarly to HPFlong NTD. In contrast, the C- terminus domain (CTD) of RafH, which is larger than the HPFlong CTD, binds to a distinct site at the platform binding center of the ribosomal small subunit. The two domain-connecting linker regions, which remain mostly disordered in earlier reported HPFlong structures, interact mainly with the anti-Shine Dalgarno sequence of the 16S rRNA.
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Affiliation(s)
- Niraj Kumar
- Structural Biology & Translation Regulation Laboratory, UNESCO-DBT, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Shivani Sharma
- Structural Biology & Translation Regulation Laboratory, UNESCO-DBT, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Prem S Kaushal
- Structural Biology & Translation Regulation Laboratory, UNESCO-DBT, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India.
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3
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Shields KE, Ranava D, Tan Y, Zhang D, Yap MNF. Epitranscriptional m6A modification of rRNA negatively impacts translation and host colonization in Staphylococcus aureus. PLoS Pathog 2024; 20:e1011968. [PMID: 38252661 PMCID: PMC10833563 DOI: 10.1371/journal.ppat.1011968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 02/01/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
Macrolides, lincosamides, and streptogramin B (MLS) are structurally distinct molecules that are among the safest antibiotics for prophylactic use and for the treatment of bacterial infections. The family of erythromycin resistance methyltransferases (Erm) invariantly install either one or two methyl groups onto the N6,6-adenosine of 2058 nucleotide (m6A2058) of the bacterial 23S rRNA, leading to bacterial cross-resistance to all MLS antibiotics. Despite extensive structural studies on the mechanism of Erm-mediated MLS resistance, how the m6A epitranscriptomic mark affects ribosome function and bacterial physiology is not well understood. Here, we show that Staphylococcus aureus cells harboring m6A2058 ribosomes are outcompeted by cells carrying unmodified ribosomes during infections and are severely impaired in colonization in the absence of an unmodified counterpart. The competitive advantage of m6A2058 ribosomes is manifested only upon antibiotic challenge. Using ribosome profiling (Ribo-Seq) and a dual-fluorescence reporter to measure ribosome occupancy and translational fidelity, we found that specific genes involved in host interactions, metabolism, and information processing are disproportionally deregulated in mRNA translation. This dysregulation is linked to a substantial reduction in translational capacity and fidelity in m6A2058 ribosomes. These findings point to a general "inefficient translation" mechanism of trade-offs associated with multidrug-resistant ribosomes.
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Affiliation(s)
- Kathryn E. Shields
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
| | - David Ranava
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Yongjun Tan
- Department of Biology, College of Arts and Sciences, Saint Louis University, St. Louis, Missouri, United States of America
| | - Dapeng Zhang
- Department of Biology, College of Arts and Sciences, Saint Louis University, St. Louis, Missouri, United States of America
- Program of Bioinformatics and Computational Biology, College of Arts and Sciences, St. Louis, Missouri, United States of America
| | - Mee-Ngan F. Yap
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri, United States of America
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
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4
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Sharma MR, Manjari SR, Agrawal EK, Keshavan P, Koripella RK, Majumdar S, Marcinkiewicz AL, Lin YP, Agrawal RK, Banavali NK. The structure of a hibernating ribosome in a Lyme disease pathogen. Nat Commun 2023; 14:6961. [PMID: 37907464 PMCID: PMC10618245 DOI: 10.1038/s41467-023-42266-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 10/04/2023] [Indexed: 11/02/2023] Open
Abstract
The spirochete bacterial pathogen Borrelia (Borreliella) burgdorferi (Bbu) affects more than 10% of the world population and causes Lyme disease in about half a million people in the US annually. Therapy for Lyme disease includes antibiotics that target the Bbu ribosome. Here we present the structure of the Bbu 70S ribosome obtained by single particle cryo-electron microscopy at 2.9 Å resolution, revealing a bound hibernation promotion factor protein and two genetically non-annotated ribosomal proteins bS22 and bL38. The ribosomal protein uL30 in Bbu has an N-terminal α-helical extension, partly resembling the mycobacterial bL37 protein, suggesting evolution of bL37 and a shorter uL30 from a longer uL30 protein. Its analogy to proteins uL30m and mL63 in mammalian mitochondrial ribosomes also suggests a plausible evolutionary pathway for expansion of protein content in mammalian mitochondrial ribosomes. Computational binding free energy predictions for antibiotics reflect subtle distinctions in antibiotic-binding sites in the Bbu ribosome. Discovery of these features in the Bbu ribosome may enable better ribosome-targeted antibiotic design for Lyme disease treatment.
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Affiliation(s)
- Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Swati R Manjari
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Ekansh K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- University of California at Berkeley, Berkeley, CA, USA
| | - Pooja Keshavan
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Apkarian Integrated Electron Microscopy Core, Emory University, Atlanta, GA, USA
| | - Soneya Majumdar
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Ashley L Marcinkiewicz
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Yi-Pin Lin
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA.
| | - Nilesh K Banavali
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, NY, USA.
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5
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Njenga R, Boele J, Öztürk Y, Koch HG. Coping with stress: How bacteria fine-tune protein synthesis and protein transport. J Biol Chem 2023; 299:105163. [PMID: 37586589 PMCID: PMC10502375 DOI: 10.1016/j.jbc.2023.105163] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Maintaining a functional proteome under different environmental conditions is challenging for every organism, in particular for unicellular organisms, such as bacteria. In order to cope with changing environments and stress conditions, bacteria depend on strictly coordinated proteostasis networks that control protein production, folding, trafficking, and degradation. Regulation of ribosome biogenesis and protein synthesis are cornerstones of this cellular adaptation in all domains of life, which is rationalized by the high energy demand of both processes and the increased resistance of translationally silent cells against internal or external poisons. Reduced protein synthesis ultimately also reduces the substrate load for protein transport systems, which are required for maintaining the periplasmic, inner, and outer membrane subproteomes. Consequences of impaired protein transport have been analyzed in several studies and generally induce a multifaceted response that includes the upregulation of chaperones and proteases and the simultaneous downregulation of protein synthesis. In contrast, generally less is known on how bacteria adjust the protein targeting and transport machineries to reduced protein synthesis, e.g., when cells encounter stress conditions or face nutrient deprivation. In the current review, which is mainly focused on studies using Escherichia coli as a model organism, we summarize basic concepts on how ribosome biogenesis and activity are regulated under stress conditions. In addition, we highlight some recent developments on how stress conditions directly impair protein targeting to the bacterial membrane. Finally, we describe mechanisms that allow bacteria to maintain the transport of stress-responsive proteins under conditions when the canonical protein targeting pathways are impaired.
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Affiliation(s)
- Robert Njenga
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany; Faculty of Biology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Julian Boele
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany.
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6
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Westhof E, Watson ZL, Zirbel CL, Cate JHD. Anionic G•U pairs in bacterial ribosomal rRNAs. RNA (NEW YORK, N.Y.) 2023; 29:1069-1076. [PMID: 37068913 DOI: 10.1261/rna.079583.123] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 04/05/2023] [Indexed: 06/18/2023]
Abstract
Wobble GU pairs (or G•U) occur frequently within double-stranded RNA helices interspersed between standard G=C and A-U Watson-Crick pairs. Another type of G•U pair interacting via their Watson-Crick edges has been observed in the A site of ribosome structures between a modified U34 in the tRNA anticodon triplet and G + 3 in the mRNA. In such pairs, the electronic structure of the U is changed with a negative charge on N3(U), resulting in two H-bonds between N1(G)…O4(U) and N2(G)…N3(U). Here, we report that such pairs occur in other highly conserved positions in ribosomal RNAs of bacteria in the absence of U modification. An anionic cis Watson-Crick G•G pair is also observed and well conserved in the small subunit. These pairs are observed in tightly folded regions.
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Affiliation(s)
- Eric Westhof
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de biologie moléculaire et cellulaire du CNRS, F-67084 Strasbourg, France
| | - Zoe L Watson
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California 94720, USA
| | - Craig L Zirbel
- Department of Mathematics and Statistics, Bowling Green State University, Bowling Green, Ohio 43403, USA
| | - Jamie H D Cate
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Innovative Genomics Institute, University of California, Berkeley, California 94720, USA
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7
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Nguyen T, Mills JC, Cho CJ. The coordinated management of ribosome and translation during injury and regeneration. Front Cell Dev Biol 2023; 11:1186638. [PMID: 37427381 PMCID: PMC10325863 DOI: 10.3389/fcell.2023.1186638] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 06/06/2023] [Indexed: 07/11/2023] Open
Abstract
Diverse acute and chronic injuries induce damage responses in the gastrointestinal (GI) system, and numerous cell types in the gastrointestinal tract demonstrate remarkable resilience, adaptability, and regenerative capacity in response to stress. Metaplasias, such as columnar and secretory cell metaplasia, are well-known adaptations that these cells make, the majority of which are epidemiologically associated with an elevated cancer risk. On a number of fronts, it is now being investigated how cells respond to injury at the tissue level, where diverse cell types that differ in proliferation capacity and differentiation state cooperate and compete with one another to participate in regeneration. In addition, the cascades or series of molecular responses that cells show are just beginning to be understood. Notably, the ribosome, a ribonucleoprotein complex that is essential for translation on the endoplasmic reticulum (ER) and in the cytoplasm, is recognized as the central organelle during this process. The highly regulated management of ribosomes as key translational machinery, and their platform, rough endoplasmic reticulum, are not only essential for maintaining differentiated cell identity, but also for achieving successful cell regeneration after injury. This review will cover in depth how ribosomes, the endoplasmic reticulum, and translation are regulated and managed in response to injury (e.g., paligenosis), as well as why this is essential for the proper adaptation of a cell to stress. For this, we will first discuss how multiple gastrointestinal organs respond to stress through metaplasia. Next, we will cover how ribosomes are generated, maintained, and degraded, in addition to the factors that govern translation. Finally, we will investigate how ribosomes and translation machinery are dynamically regulated in response to injury. Our increased understanding of this overlooked cell fate decision mechanism will facilitate the discovery of novel therapeutic targets for gastrointestinal tract tumors, focusing on ribosomes and translation machinery.
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Affiliation(s)
- Thanh Nguyen
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Jason C. Mills
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, TX, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, United States
| | - Charles J. Cho
- Department of Medicine, Baylor College of Medicine, Houston, TX, United States
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8
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Morgan CE, Kang YS, Green AB, Smith KP, Dowgiallo MG, Miller BC, Chiaraviglio L, Truelson KA, Zulauf KE, Rodriguez S, Kang AD, Manetsch R, Yu EW, Kirby JE. Streptothricin F is a bactericidal antibiotic effective against highly drug-resistant gram-negative bacteria that interacts with the 30S subunit of the 70S ribosome. PLoS Biol 2023; 21:e3002091. [PMID: 37192172 DOI: 10.1371/journal.pbio.3002091] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 03/22/2023] [Indexed: 05/18/2023] Open
Abstract
The streptothricin natural product mixture (also known as nourseothricin) was discovered in the early 1940s, generating intense initial interest because of excellent gram-negative activity. Here, we establish the activity spectrum of nourseothricin and its main components, streptothricin F (S-F, 1 lysine) and streptothricin D (S-D, 3 lysines), purified to homogeneity, against highly drug-resistant, carbapenem-resistant Enterobacterales (CRE) and Acinetobacter baumannii. For CRE, the MIC50 and MIC90 for S-F and S-D were 2 and 4 μM, and 0.25 and 0.5 μM, respectively. S-F and nourseothricin showed rapid, bactericidal activity. S-F and S-D both showed approximately 40-fold greater selectivity for prokaryotic than eukaryotic ribosomes in in vitro translation assays. In vivo, delayed renal toxicity occurred at >10-fold higher doses of S-F compared with S-D. Substantial treatment effect of S-F in the murine thigh model was observed against the otherwise pandrug-resistant, NDM-1-expressing Klebsiella pneumoniae Nevada strain with minimal or no toxicity. Cryo-EM characterization of S-F bound to the A. baumannii 70S ribosome defines extensive hydrogen bonding of the S-F steptolidine moiety, as a guanine mimetic, to the 16S rRNA C1054 nucleobase (Escherichia coli numbering) in helix 34, and the carbamoylated gulosamine moiety of S-F with A1196, explaining the high-level resistance conferred by corresponding mutations at the residues identified in single rrn operon E. coli. Structural analysis suggests that S-F probes the A-decoding site, which potentially may account for its miscoding activity. Based on unique and promising activity, we suggest that the streptothricin scaffold deserves further preclinical exploration as a potential therapeutic for drug-resistant, gram-negative pathogens.
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Affiliation(s)
- Christopher E Morgan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - Yoon-Suk Kang
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Alex B Green
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Kenneth P Smith
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Matthew G Dowgiallo
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Brandon C Miller
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, United States of America
| | - Lucius Chiaraviglio
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Katherine A Truelson
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Katelyn E Zulauf
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Shade Rodriguez
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
| | - Anthony D Kang
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Roman Manetsch
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts, United States of America
- Department of Pharmaceutical Sciences, Northeastern University, Boston, Massachusetts, United States of America
- Center for Drug Discovery, Northeastern University, Boston, Massachusetts, United States of America
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, United States of America
| | - James E Kirby
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
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9
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Naschberger A, Mosebach L, Tobiasson V, Kuhlgert S, Scholz M, Perez-Boerema A, Ho TTH, Vidal-Meireles A, Takahashi Y, Hippler M, Amunts A. Algal photosystem I dimer and high-resolution model of PSI-plastocyanin complex. NATURE PLANTS 2022; 8:1191-1201. [PMID: 36229605 PMCID: PMC9579051 DOI: 10.1038/s41477-022-01253-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 09/02/2022] [Indexed: 05/29/2023]
Abstract
Photosystem I (PSI) enables photo-electron transfer and regulates photosynthesis in the bioenergetic membranes of cyanobacteria and chloroplasts. Being a multi-subunit complex, its macromolecular organization affects the dynamics of photosynthetic membranes. Here we reveal a chloroplast PSI from the green alga Chlamydomonas reinhardtii that is organized as a homodimer, comprising 40 protein subunits with 118 transmembrane helices that provide scaffold for 568 pigments. Cryogenic electron microscopy identified that the absence of PsaH and Lhca2 gives rise to a head-to-head relative orientation of the PSI-light-harvesting complex I monomers in a way that is essentially different from the oligomer formation in cyanobacteria. The light-harvesting protein Lhca9 is the key element for mediating this dimerization. The interface between the monomers is lacking PsaH and thus partially overlaps with the surface area that would bind one of the light-harvesting complex II complexes in state transitions. We also define the most accurate available PSI-light-harvesting complex I model at 2.3 Å resolution, including a flexibly bound electron donor plastocyanin, and assign correct identities and orientations to all the pigments, as well as 621 water molecules that affect energy transfer pathways.
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Affiliation(s)
- Andreas Naschberger
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Laura Mosebach
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Victor Tobiasson
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Sebastian Kuhlgert
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Martin Scholz
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Annemarie Perez-Boerema
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden
| | - Thi Thu Hoai Ho
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
- Faculty of Fisheries, University of Agriculture and Forestry, Hue University, Hue, Vietnam
| | - André Vidal-Meireles
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany
| | - Yuichiro Takahashi
- Research Institute for Interdisciplinary Science, Okayama University, Okayama, Japan
- Japan Science and Technology Agency-CREST, Saitama, Japan
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Münster, Germany.
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Japan.
| | - Alexey Amunts
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Solna, Sweden.
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10
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Ranava D, Scheidler CM, Pfanzelt M, Fiedler M, Sieber SA, Schneider S, Yap MNF. Bidirectional sequestration between a bacterial hibernation factor and a glutamate metabolizing protein. Proc Natl Acad Sci U S A 2022; 119:e2207257119. [PMID: 36122228 PMCID: PMC9522360 DOI: 10.1073/pnas.2207257119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/29/2022] [Indexed: 11/18/2022] Open
Abstract
Bacterial hibernating 100S ribosomes (the 70S dimers) are excluded from translation and are protected from ribonucleolytic degradation, thereby promoting long-term viability and increased regrowth. No extraribosomal target of any hibernation factor has been reported. Here, we discovered a previously unrecognized binding partner (YwlG) of hibernation-promoting factor (HPF) in the human pathogen Staphylococcus aureus. YwlG is an uncharacterized virulence factor in S. aureus. We show that the HPF-YwlG interaction is direct, independent of ribosome binding, and functionally linked to cold adaptation and glucose metabolism. Consistent with the distant resemblance of YwlG to the hexameric structures of nicotinamide adenine dinucleotide (NAD)-specific glutamate dehydrogenases (GDHs), YwlG overexpression can compensate for a loss of cellular GDH activity. The reduced abundance of 100S complexes and the suppression of YwlG-dependent GDH activity provide evidence for a two-way sequestration between YwlG and HPF. These findings reveal an unexpected layer of regulation linking the biogenesis of 100S ribosomes to glutamate metabolism.
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Affiliation(s)
- David Ranava
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | | | - Martin Pfanzelt
- Department of Chemistry, Chair of Organic Chemistry III, Center for Functional Protein Assemblies (CPA), Technische Universität München, 80333 Garching, Germany
| | - Michaela Fiedler
- Department of Chemistry, Chair of Organic Chemistry III, Center for Functional Protein Assemblies (CPA), Technische Universität München, 80333 Garching, Germany
| | - Stephan A. Sieber
- Department of Chemistry, Chair of Organic Chemistry III, Center for Functional Protein Assemblies (CPA), Technische Universität München, 80333 Garching, Germany
| | - Sabine Schneider
- Department of Chemistry, Ludwig-Maximilians-Universität München, 81377 Munich, Germany
| | - Mee-Ngan F. Yap
- Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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11
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Cerullo F, Filbeck S, Patil PR, Hung HC, Xu H, Vornberger J, Hofer FW, Schmitt J, Kramer G, Bukau B, Hofmann K, Pfeffer S, Joazeiro CAP. Bacterial ribosome collision sensing by a MutS DNA repair ATPase paralogue. Nature 2022; 603:509-514. [PMID: 35264791 DOI: 10.1038/s41586-022-04487-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022]
Abstract
Ribosome stalling during translation is detrimental to cellular fitness, but how this is sensed and elicits recycling of ribosomal subunits and quality control of associated mRNA and incomplete nascent chains is poorly understood1,2. Here we uncover Bacillus subtilis MutS2, a member of the conserved MutS family of ATPases that function in DNA mismatch repair3, as an unexpected ribosome-binding protein with an essential function in translational quality control. Cryo-electron microscopy analysis of affinity-purified native complexes shows that MutS2 functions in sensing collisions between stalled and translating ribosomes and suggests how ribosome collisions can serve as platforms to deploy downstream processes: MutS2 has an RNA endonuclease small MutS-related (SMR) domain, as well as an ATPase/clamp domain that is properly positioned to promote ribosomal subunit dissociation, which is a requirement both for ribosome recycling and for initiation of ribosome-associated protein quality control (RQC). Accordingly, MutS2 promotes nascent chain modification with alanine-tail degrons-an early step in RQC-in an ATPase domain-dependent manner. The relevance of these observations is underscored by evidence of strong co-occurrence of MutS2 and RQC genes across bacterial phyla. Overall, the findings demonstrate a deeply conserved role for ribosome collisions in mounting a complex response to the interruption of translation within open reading frames.
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Affiliation(s)
- Federico Cerullo
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Sebastian Filbeck
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Pratik Rajendra Patil
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Hao-Chih Hung
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Haifei Xu
- Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA
| | - Julia Vornberger
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Florian W Hofer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Jaro Schmitt
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Guenter Kramer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Bernd Bukau
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Kay Hofmann
- Institute for Genetics, University of Cologne, Cologne, Germany
| | - Stefan Pfeffer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany.
| | - Claudio A P Joazeiro
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany. .,Department of Molecular Medicine, Scripps Florida, Jupiter, FL, USA.
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12
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Yaeshima C, Murata N, Ishino S, Sagawa I, Ito K, Uchiumi T. A novel ribosome-dimerization protein found in the hyperthermophilic archaeon Pyrococcus furiosus using ribosome-associated proteomics. Biochem Biophys Res Commun 2022; 593:116-121. [DOI: 10.1016/j.bbrc.2022.01.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022]
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13
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Misal SA, Zhao B, Reilly JP. Interpretation of Anomalously Long Crosslinks in Ribosome Crosslinking reveals the ribosome interaction in stationary phase E. coli. RSC Chem Biol 2022; 3:886-894. [PMID: 35866168 PMCID: PMC9257603 DOI: 10.1039/d2cb00101b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 05/15/2022] [Indexed: 11/21/2022] Open
Abstract
Crosslinking mass spectrometry (XL-MS) of bacterial ribosomes revealed the dynamic intra and intermolecular interactions within the ribosome structure. It has been also extended to capture the interactions of ribosome binding...
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Affiliation(s)
- Santosh A Misal
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
| | - Bingqing Zhao
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
| | - James P Reilly
- Department of Chemistry, Indiana University 800 East Kirkwood Avenue Bloomington IN 47405 USA
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14
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Maki Y, Yoshida H. Ribosomal Hibernation-Associated Factors in Escherichia coli. Microorganisms 2021; 10:microorganisms10010033. [PMID: 35056482 PMCID: PMC8778775 DOI: 10.3390/microorganisms10010033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 12/17/2021] [Accepted: 12/21/2021] [Indexed: 01/30/2023] Open
Abstract
Bacteria convert active 70S ribosomes to inactive 100S ribosomes to survive under various stress conditions. This state, in which the ribosome loses its translational activity, is known as ribosomal hibernation. In gammaproteobacteria such as Escherichia coli, ribosome modulation factor and hibernation-promoting factor are involved in forming 100S ribosomes. The expression of ribosome modulation factor is regulated by (p)ppGpp (which is induced by amino acid starvation), cAMP-CRP (which is stimulated by reduced metabolic energy), and transcription factors involved in biofilm formation. This indicates that the formation of 100S ribosomes is an important strategy for bacterial survival under various stress conditions. In recent years, the structures of 100S ribosomes from various bacteria have been reported, enhancing our understanding of the 100S ribosome. Here, we present previous findings on the 100S ribosome and related proteins and describe the stress-response pathways involved in ribosomal hibernation.
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15
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Aibara S, Dienemann C, Cramer P. Structure of an inactive RNA polymerase II dimer. Nucleic Acids Res 2021; 49:10747-10755. [PMID: 34530439 PMCID: PMC8501987 DOI: 10.1093/nar/gkab783] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/24/2021] [Accepted: 09/14/2021] [Indexed: 02/05/2023] Open
Abstract
Eukaryotic gene transcription is carried out by three RNA polymerases: Pol I, Pol II and Pol III. Although it has long been known that Pol I can form homodimers, it is unclear whether and how the two other RNA polymerases dimerize. Here we present the cryo-electron microscopy (cryo-EM) structure of a mammalian Pol II dimer at 3.5 Å resolution. The structure differs from the Pol I dimer and reveals that one Pol II copy uses its RPB4-RPB7 stalk to penetrate the active centre cleft of the other copy, and vice versa, giving rise to a molecular handshake. The polymerase clamp domain is displaced and mobile, and the RPB7 oligonucleotide-binding fold mimics the DNA–RNA hybrid that occupies the cleft during active transcription. The Pol II dimer is incompatible with nucleic acid binding as required for transcription and may represent an inactive storage form of the polymerase.
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Affiliation(s)
- Shintaro Aibara
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Christian Dienemann
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077, Göttingen, Germany
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16
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Li Y, Sharma MR, Koripella RK, Banavali NK, Agrawal RK, Ojha AK. Ribosome hibernation: a new molecular framework for targeting nonreplicating persisters of mycobacteria. MICROBIOLOGY-SGM 2021; 167. [PMID: 33555244 DOI: 10.1099/mic.0.001035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Treatment of tuberculosis requires a multi-drug regimen administered for at least 6 months. The long-term chemotherapy is attributed in part to a minor subpopulation of nonreplicating Mycobacterium tuberculosis cells that exhibit phenotypic tolerance to antibiotics. The origins of these cells in infected hosts remain unclear. Here we discuss some recent evidence supporting the hypothesis that hibernation of ribosomes in M. tuberculosis, induced by zinc starvation, could be one of the primary mechanisms driving the development of nonreplicating persisters in hosts. We further analyse inconsistencies in previously reported studies to clarify the molecular principles underlying mycobacterial ribosome hibernation.
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Affiliation(s)
- Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Manjuli R Sharma
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Nilesh K Banavali
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA.,Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA.,Department of Biomedical Sciences, University at Albany, Albany, NY, USA
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17
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Kumar N, Sharma S, Kaushal PS. Protein synthesis in Mycobacterium tuberculosis as a potential target for therapeutic interventions. Mol Aspects Med 2021; 81:101002. [PMID: 34344520 DOI: 10.1016/j.mam.2021.101002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 07/11/2021] [Accepted: 07/16/2021] [Indexed: 12/18/2022]
Abstract
Mycobacterium tuberculosis (Mtb) causes one of humankind's deadliest diseases, tuberculosis. Mtb protein synthesis machinery possesses several unique species-specific features, including its ribosome that carries two mycobacterial specific ribosomal proteins, bL37 and bS22, and ribosomal RNA segments. Since the protein synthesis is a vital cellular process that occurs on the ribosome, a detailed knowledge of the structure and function of mycobacterial ribosomes is essential to understand the cell's proteome by translation regulation. Like in many bacterial species such as Bacillus subtilis and Streptomyces coelicolor, two distinct populations of ribosomes have been identified in Mtb. Under low-zinc conditions, Mtb ribosomal proteins S14, S18, L28, and L33 are replaced with their non-zinc binding paralogues. Depending upon the nature of physiological stress, species-specific modulation of translation by stress factors and toxins that interact with the ribosome have been reported. In addition, about one-fourth of messenger RNAs in mycobacteria have been reported to be leaderless, i.e., without 5' UTR regions. However, the mechanism by which they are recruited to the Mtb ribosome is not understood. In this review, we highlight the mycobacteria-specific features of the translation apparatus and propose exploiting these features to improve the efficacy and specificity of existing antibiotics used to treat tuberculosis.
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Affiliation(s)
- Niraj Kumar
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Shivani Sharma
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India
| | - Prem S Kaushal
- Structural Biology & Translation Regulation Laboratory, Regional Centre for Biotechnology, NCR Biotech Science Cluster, Faridabad, 121 001, India.
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18
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Hibernation-Promoting Factor Sequesters Staphylococcus aureus Ribosomes to Antagonize RNase R-Mediated Nucleolytic Degradation. mBio 2021; 12:e0033421. [PMID: 34253058 PMCID: PMC8406268 DOI: 10.1128/mbio.00334-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Bacterial and eukaryotic hibernation factors prevent translation by physically blocking the decoding center of ribosomes, a phenomenon called ribosome hibernation that often occurs in response to nutrient deprivation. The human pathogen Staphylococcus aureus lacking the sole hibernation factor HPF undergoes massive ribosome degradation via an unknown pathway. Using genetic and biochemical approaches, we find that inactivating the 3′-to-5′ exonuclease RNase R suppresses ribosome degradation in the Δhpf mutant. In vitro cell-free degradation assays confirm that 30S and 70S ribosomes isolated from the Δhpf mutant are extremely susceptible to RNase R, in stark contrast to nucleolytic resistance of the HPF-bound 70S and 100S complexes isolated from the wild type. In the absence of HPF, specific S. aureus 16S rRNA helices are sensitive to nucleolytic cleavage. These RNase hot spots are distinct from that found in the Escherichia coli ribosomes. S. aureus RNase R is associated with ribosomes, but unlike the E. coli counterpart, it is not regulated by general stressors and acetylation. The results not only highlight key differences between the evolutionarily conserved RNase R homologs but also provide direct evidence that HPF preserves ribosome integrity beyond its role in translational avoidance, thereby poising the hibernating ribosomes for rapid resumption of translation.
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19
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Usachev KS, Yusupov MM, Validov SZ. Hibernation as a Stage of Ribosome Functioning. BIOCHEMISTRY (MOSCOW) 2021; 85:1434-1442. [PMID: 33280583 DOI: 10.1134/s0006297920110115] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In response to stress, eubacteria reduce the level of protein synthesis and either disassemble ribosomes into the 30S and 50S subunits or turn them into translationally inactive 70S and 100S complexes. This helps the cell to solve two principal tasks: (i) to reduce the cost of protein biosynthesis under unfavorable conditions, and (ii) to preserve functional ribosomes for rapid recovery of protein synthesis until favorable conditions are restored. All known genes for ribosome silencing factors and hibernation proteins are located in the operons associated with the response to starvation as one of the stress factors, which helps the cells to coordinate the slowdown of protein synthesis with the overall stress response. It is possible that hibernation systems work as regulators that coordinate the intensity of protein synthesis with the energy state of bacterial cell. Taking into account the limited amount of nutrients in natural conditions and constant pressure of other stress factors, bacterial ribosome should remain most of time in a complex with the silencing/hibernation proteins. Therefore, hibernation is an additional stage between the ribosome recycling and translation initiation, at which the ribosome is maintained in a "preserved" state in the form of separate subunits, non-translating 70S particles, or 100S dimers. The evolution of the ribosome hibernation has occurred within a very long period of time; ribosome hibernation is a conserved mechanism that is essential for maintaining the energy- and resource-consuming process of protein biosynthesis in organisms living in changing environment under stress conditions.
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Affiliation(s)
- K S Usachev
- Kazan Federal University, Kazan, 420008, Russia
| | - M M Yusupov
- Kazan Federal University, Kazan, 420008, Russia. .,Institute of Genetics and Molecular and Cellular Biology, Illkirch-Graffenstaden, 67400, France
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20
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Cryo-EM Determination of Eravacycline-Bound Structures of the Ribosome and the Multidrug Efflux Pump AdeJ of Acinetobacter baumannii. mBio 2021; 12:e0103121. [PMID: 34044590 PMCID: PMC8263017 DOI: 10.1128/mbio.01031-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antibiotic-resistant strains of the Gram-negative pathogen Acinetobacter baumannii have emerged as a significant global health threat. One successful therapeutic option to treat bacterial infections has been to target the bacterial ribosome. However, in many cases, multidrug efflux pumps within the bacterium recognize and extrude these clinically important antibiotics designed to inhibit the protein synthesis function of the bacterial ribosome. Thus, multidrug efflux within A. baumannii and other highly drug-resistant strains is a major cause of failure of drug-based treatments of infectious diseases. We here report the first structures of the Acinetobacterdrug efflux (Ade)J pump in the presence of the antibiotic eravacycline, using single-particle cryo-electron microscopy (cryo-EM). We also describe cryo-EM structures of the eravacycline-bound forms of the A. baumannii ribosome, including the 70S, 50S, and 30S forms. Our data indicate that the AdeJ pump primarily uses hydrophobic interactions to bind eravacycline, while the 70S ribosome utilizes electrostatic interactions to bind this drug. Our work here highlights how an antibiotic can bind multiple bacterial targets through different mechanisms and potentially enables drug optimization by taking advantage of these different modes of ligand binding.
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21
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Gerovac M, Vogel J, Smirnov A. The World of Stable Ribonucleoproteins and Its Mapping With Grad-Seq and Related Approaches. Front Mol Biosci 2021; 8:661448. [PMID: 33898526 PMCID: PMC8058203 DOI: 10.3389/fmolb.2021.661448] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 03/04/2021] [Indexed: 12/13/2022] Open
Abstract
Macromolecular complexes of proteins and RNAs are essential building blocks of cells. These stable supramolecular particles can be viewed as minimal biochemical units whose structural organization, i.e., the way the RNA and the protein interact with each other, is directly linked to their biological function. Whether those are dynamic regulatory ribonucleoproteins (RNPs) or integrated molecular machines involved in gene expression, the comprehensive knowledge of these units is critical to our understanding of key molecular mechanisms and cell physiology phenomena. Such is the goal of diverse complexomic approaches and in particular of the recently developed gradient profiling by sequencing (Grad-seq). By separating cellular protein and RNA complexes on a density gradient and quantifying their distributions genome-wide by mass spectrometry and deep sequencing, Grad-seq charts global landscapes of native macromolecular assemblies. In this review, we propose a function-based ontology of stable RNPs and discuss how Grad-seq and related approaches transformed our perspective of bacterial and eukaryotic ribonucleoproteins by guiding the discovery of new RNA-binding proteins and unusual classes of noncoding RNAs. We highlight some methodological aspects and developments that permit to further boost the power of this technique and to look for exciting new biology in understudied and challenging biological models.
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Affiliation(s)
- Milan Gerovac
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
| | - Jörg Vogel
- Institute of Molecular Infection Biology (IMIB), University of Würzburg, Würzburg, Germany
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), Würzburg, Germany
| | - Alexandre Smirnov
- UMR 7156—Génétique Moléculaire, Génomique, Microbiologie (GMGM), University of Strasbourg, CNRS, Strasbourg, France
- University of Strasbourg Institute for Advanced Study (USIAS), Strasbourg, France
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22
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Prossliner T, Gerdes K, Sørensen MA, Winther KS. Hibernation factors directly block ribonucleases from entering the ribosome in response to starvation. Nucleic Acids Res 2021; 49:2226-2239. [PMID: 33503254 PMCID: PMC7913689 DOI: 10.1093/nar/gkab017] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/03/2021] [Accepted: 01/11/2021] [Indexed: 11/18/2022] Open
Abstract
Ribosome hibernation is a universal translation stress response found in bacteria as well as plant plastids. The term was coined almost two decades ago and despite recent insights including detailed cryo-EM structures, the physiological role and underlying molecular mechanism of ribosome hibernation has remained unclear. Here, we demonstrate that Escherichia coli hibernation factors RMF, HPF and RaiA (HFs) concurrently confer ribosome hibernation. In response to carbon starvation and resulting growth arrest, we observe that HFs protect ribosomes at the initial stage of starvation. Consistently, a deletion mutant lacking all three factors (ΔHF) is severely inhibited in regrowth from starvation. ΔHF cells increasingly accumulate 70S ribosomes harbouring fragmented rRNA, while rRNA in wild-type 100S dimers is intact. RNA fragmentation is observed to specifically occur at HF-associated sites in 16S rRNA of assembled 70S ribosomes. Surprisingly, degradation of the 16S rRNA 3′-end is decreased in cells lacking conserved endoribonuclease YbeY and exoribonuclease RNase R suggesting that HFs directly block these ribonucleases from accessing target sites in the ribosome.
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Affiliation(s)
- Thomas Prossliner
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
| | | | - Michael Askvad Sørensen
- Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, DK-2200 Copenhagen, Denmark
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23
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An Analysis of the Novel Fluorocycline TP-6076 Bound to Both the Ribosome and Multidrug Efflux Pump AdeJ from Acinetobacter baumannii. mBio 2021; 13:e0373221. [PMID: 35100868 PMCID: PMC8805024 DOI: 10.1128/mbio.03732-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Antibiotic resistance among bacterial pathogens continues to pose a serious global health threat. Multidrug-resistant (MDR) strains of the Gram-negative organism Acinetobacter baumannii utilize a number of resistance determinants to evade current antibiotics. One of the major resistance mechanisms employed by these pathogens is the use of multidrug efflux pumps. These pumps extrude xenobiotics directly out of bacterial cells, resulting in treatment failures when common antibiotics are administered. Here, the structure of the novel tetracycline antibiotic TP-6076, bound to both the Acinetobacter drug efflux pump AdeJ and the ribosome from Acinetobacter baumannii, using single-particle cryo-electron microscopy (cryo-EM), is elucidated. In this work, the structure of the AdeJ-TP-6076 complex is solved, and we show that AdeJ utilizes a network of hydrophobic interactions to recognize this fluorocycline. Concomitant with this, we elucidate three structures of TP-6076 bound to the A. baumannii ribosome and determine that its binding is stabilized largely by electrostatic interactions. We then compare the differences in binding modes between TP-6076 and the related tetracycline antibiotic eravacycline in both targets. These differences suggest that modifications to the tetracycline core may be able to alter AdeJ binding while maintaining interactions with the ribosome. Together, this work highlights how different mechanisms are used to stabilize the binding of tetracycline-based compounds to unique bacterial targets and provides guidance for the future clinical development of tetracycline antibiotics. IMPORTANCE Treatment of antibiotic-resistant organisms such as A. baumannii represents an ongoing issue for modern medicine. The multidrug efflux pump AdeJ serves as a major resistance determinant in A. baumannii through its action of extruding antibiotics from the cell. In this work, we use cryo-EM to show how AdeJ recognizes the experimental tetracycline antibiotic TP-6076 and prevents this drug from interacting with the A. baumannii ribosome. Since AdeJ and the ribosome use different binding modes to stabilize interactions with TP-6076, exploiting these differences may guide future drug development for combating antibiotic-resistant A. baumannii and potentially other strains of MDR bacteria.
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24
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Li Y, Keshavan P, Corro JH, Koripella RK, Agrawal RK, Ojha AK. Purification of Hibernating and Active C- Ribosomes from Zinc-Starved Mycobacteria. Methods Mol Biol 2021; 2314:151-166. [PMID: 34235651 DOI: 10.1007/978-1-0716-1460-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Zinc starvation in Mycobacterium smegmatis and Mycobacterium tuberculosis induces ribosome remodeling and hibernation. Remodeling involves replacement of C+ ribosomal (r-) proteins containing the zinc-binding CXXC motif with their C- paralogues without the motif. Hibernation is characterized by binding of mycobacterial-specific protein Y (Mpy) to 70S C- ribosomes, stabilizing the ribosome in an inactive state that is also resistant to kanamycin and streptomycin. We observed that ribosome remodeling and hibernation occur at two different concentrations of cellular zinc. Here, we describe the methods to purify hibernating and active forms of C- ribosomes from zinc-starved mycobacteria, along with purification of C+ ribosomes from zinc-rich mycobacterial cells. In vitro analysis of these distinct types of ribosomes will facilitate screening of small molecule inhibitors of ribosome hibernation for improved therapeutics against mycobacterial infections.
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Affiliation(s)
- Yunlong Li
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Pooja Keshavan
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Jamie H Corro
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Ravi K Koripella
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Rajendra K Agrawal
- Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY, USA
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA
| | - Anil K Ojha
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY, USA.
- Department of Biomedical Sciences, University at Albany, Albany, NY, USA.
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25
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Theng S, Williamson KS, Franklin MJ. Role of Hibernation Promoting Factor in Ribosomal Protein Stability during Pseudomonas aeruginosa Dormancy. Int J Mol Sci 2020; 21:E9494. [PMID: 33327444 PMCID: PMC7764885 DOI: 10.3390/ijms21249494] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 01/02/2023] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that causes biofilm-associated infections. P. aeruginosa can survive in a dormant state with reduced metabolic activity in nutrient-limited environments, including the interiors of biofilms. When entering dormancy, the bacteria undergo metabolic remodeling, which includes reduced translation and degradation of cellular proteins. However, a supply of essential macromolecules, such as ribosomes, are protected from degradation during dormancy. The small ribosome-binding proteins, hibernation promoting factor (HPF) and ribosome modulation factor (RMF), inhibit translation by inducing formation of inactive 70S and 100S ribosome monomers and dimers. The inactivated ribosomes are protected from the initial steps in ribosome degradation, including endonuclease cleavage of the ribosomal RNA (rRNA). Here, we characterized the role of HPF in ribosomal protein (rProtein) stability and degradation during P. aeruginosa nutrient limitation. We determined the effect of the physiological status of P. aeruginosa prior to starvation on its ability to recover from starvation, and on its rRNA and rProtein stability during cell starvation. The results show that the wild-type strain and a stringent response mutant (∆relA∆spoT strain) maintain high cellular abundances of the rProteins L5 and S13 over the course of eight days of starvation. In contrast, the abundances of L5 and S13 reduce in the ∆hpf mutant cells. The loss of rProteins in the ∆hpf strain is dependent on the physiology of the cells prior to starvation. The greatest rProtein loss occurs when cells are first cultured to stationary phase prior to starvation, with less rProtein loss in the ∆hpf cells that are first cultured to exponential phase or in balanced minimal medium. Regardless of the pre-growth conditions, P. aeruginosa recovery from starvation and the integrity of its rRNA are impaired in the absence of HPF. The results indicate that protein remodeling during P. aeruginosa starvation includes the degradation of rProteins, and that HPF is essential to prevent rProtein loss in starved P. aeruginosa. The results also indicate that HPF is produced throughout cell growth, and that regardless of the cellular physiological status, HPF is required to protect against ribosome loss when the cells subsequently enter starvation phase.
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Affiliation(s)
- Sokuntheary Theng
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
| | - Kerry S. Williamson
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
| | - Michael J. Franklin
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA; (S.T.); (K.S.W.)
- Center for Biofilm Engineering, Montana State University, Bozeman, MT 59717, USA
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Murphy EL, Singh KV, Avila B, Kleffmann T, Gregory ST, Murray BE, Krause KL, Khayat R, Jogl G. Cryo-electron microscopy structure of the 70S ribosome from Enterococcus faecalis. Sci Rep 2020; 10:16301. [PMID: 33004869 PMCID: PMC7530986 DOI: 10.1038/s41598-020-73199-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 09/11/2020] [Indexed: 01/21/2023] Open
Abstract
Enterococcus faecalis is a gram-positive organism responsible for serious infections in humans, but as with many bacterial pathogens, resistance has rendered a number of commonly used antibiotics ineffective. Here, we report the cryo-EM structure of the E. faecalis 70S ribosome to a global resolution of 2.8 Å. Structural differences are clustered in peripheral and solvent exposed regions when compared with Escherichia coli, whereas functional centres, including antibiotic binding sites, are similar to other bacterial ribosomes. Comparison of intersubunit conformations among five classes obtained after three-dimensional classification identifies several rotated states. Large ribosomal subunit protein bL31, which forms intersubunit bridges to the small ribosomal subunit, assumes different conformations in the five classes, revealing how contacts to the small subunit are maintained throughout intersubunit rotation. A tRNA observed in one of the five classes is positioned in a chimeric pe/E position in a rotated ribosomal state. The 70S ribosome structure of E. faecalis now extends our knowledge of bacterial ribosome structures and may serve as a basis for the development of novel antibiotic compounds effective against this pathogen.
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Affiliation(s)
- Eileen L. Murphy
- grid.40263.330000 0004 1936 9094Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912 USA
| | - Kavindra V. Singh
- grid.267308.80000 0000 9206 2401Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, TX 77030 USA ,grid.267308.80000 0000 9206 2401Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center, Houston, TX 77030 USA
| | - Bryant Avila
- grid.254250.40000 0001 2264 7145Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031 USA
| | - Torsten Kleffmann
- grid.29980.3a0000 0004 1936 7830Department of Biochemistry, University of Otago, Dunedin, 9054 New Zealand
| | - Steven T. Gregory
- grid.20431.340000 0004 0416 2242Department of Cell and Molecular Biology, The University of Rhode Island, Kingston, RI 02881 USA
| | - Barbara E. Murray
- grid.267308.80000 0000 9206 2401Division of Infectious Diseases, Department of Internal Medicine, University of Texas Health Science Center, Houston, TX 77030 USA ,grid.267308.80000 0000 9206 2401Center for Antimicrobial Resistance and Microbial Genomics, University of Texas Health Science Center, Houston, TX 77030 USA ,grid.267308.80000 0000 9206 2401Department of Microbiology and Molecular Genetics, University of Texas Health Science Center, Houston, TX 77030 USA
| | - Kurt L. Krause
- grid.29980.3a0000 0004 1936 7830Department of Biochemistry, University of Otago, Dunedin, 9054 New Zealand
| | - Reza Khayat
- grid.254250.40000 0001 2264 7145Department of Chemistry and Biochemistry, The City College of New York, New York, NY 10031 USA
| | - Gerwald Jogl
- grid.40263.330000 0004 1936 9094Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912 USA
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Wiederstein M, Sippl MJ. TopMatch-web: pairwise matching of large assemblies of protein and nucleic acid chains in 3D. Nucleic Acids Res 2020; 48:W31-W35. [PMID: 32479639 PMCID: PMC7319569 DOI: 10.1093/nar/gkaa366] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/20/2020] [Accepted: 05/29/2020] [Indexed: 11/13/2022] Open
Abstract
Frequently, the complete functional units of biological molecules are assemblies of protein and nucleic acid chains. Stunning examples are the complex structures of ribosomes. Here, we present TopMatch-web, a computational tool for the study of the three-dimensional structure, function and evolution of such molecules. The unique feature of TopMatch is its ability to match the protein as well as nucleic acid chains of complete molecular assemblies simultaneously. The resulting structural alignments are visualized instantly using the high-performance molecular viewer NGL. We use the mitochondrial ribosomes of human and yeast as an example to demonstrate the capabilities of TopMatch-web. The service responds immediately, enabling the interactive study of many pairwise alignments of large molecular assemblies in a single session. TopMatch-web is freely accessible at https://topmatch.services.came.sbg.ac.at.
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Affiliation(s)
- Markus Wiederstein
- Paris-Lodron-University of Salzburg, Department of Biosciences, Hellbrunner Str. 34, 5020 Salzburg, Austria
| | - Manfred J Sippl
- Paris-Lodron-University of Salzburg, Department of Biosciences, Hellbrunner Str. 34, 5020 Salzburg, Austria
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28
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Functional Characterization of the Pseudomonas aeruginosa Ribosome Hibernation-Promoting Factor. J Bacteriol 2020; 202:JB.00280-20. [PMID: 32900865 DOI: 10.1128/jb.00280-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022] Open
Abstract
Hibernation-promoting factor (HPF) is a ribosomal accessory protein that inactivates ribosomes during bacterial starvation. In Pseudomonas aeruginosa, HPF protects ribosome integrity while the cells are dormant. The sequence of HPF has diverged among bacteria but contains conserved charged amino acids in its two alpha helices that interact with the rRNA. Here, we characterized the function of HPF in P. aeruginosa by performing mutagenesis of the conserved residues and then assaying mutant HPF alleles for their ability to protect ribosome integrity of starved P. aeruginosa cells. The results show that HPF functionally tolerates point mutations in charged residues and in the conserved Y71 residue as well as a C-terminal truncation. Double and triple mutations of charged residues in helix 1 in combination with a Y71F substitution reduce HPF activity. Screening for single point mutations that caused impaired HPF activity identified additional substitutions in the two HPF alpha helices. However, alanine substitutions in equivalent positions restored HPF activity, indicating that HPF is tolerant to mutations that do not disrupt the protein structure. Surprisingly, heterologous HPFs from Gram-positive bacteria that have long C-terminal domains functionally complement the P. aeruginosa Δhpf mutant, suggesting that HPF may play a similar role in ribosome protection in other bacterial species. Collectively, the results show that HPF has diverged among bacteria and is tolerant to most single amino acid substitutions. The Y71 residue in combination with helix 1 is important for the functional role of HPF in ribosome protection during bacterial starvation and resuscitation of the bacteria from dormancy.IMPORTANCE In most environments, bacteria experience conditions where nutrients may be readily abundant or where nutrients are limited. Under nutrient limitation conditions, even non-spore-forming bacteria may enter a dormant state. Dormancy is accompanied by a variety of cellular physiological changes that are required for the cells to remain viable during dormancy and to resuscitate when nutrients become available. Among the physiological changes that occur in dormant bacteria is the inactivation and preservation of ribosomes by the dormancy protein, hibernation-promoting factor (HPF). In this study, we characterized the activity of HPF of Pseudomonas aeruginosa, an opportunistic pathogen that causes persistent infections, and analyzed the role of HPF in ribosome protection and bacterial survival during dormancy.
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Tüting C, Iacobucci C, Ihling CH, Kastritis PL, Sinz A. Structural analysis of 70S ribosomes by cross-linking/mass spectrometry reveals conformational plasticity. Sci Rep 2020; 10:12618. [PMID: 32724211 PMCID: PMC7387497 DOI: 10.1038/s41598-020-69313-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 07/10/2020] [Indexed: 12/14/2022] Open
Abstract
The ribosome is not only a highly complex molecular machine that translates the genetic information into proteins, but also an exceptional specimen for testing and optimizing cross-linking/mass spectrometry (XL-MS) workflows. Due to its high abundance, ribosomal proteins are frequently identified in proteome-wide XL-MS studies of cells or cell extracts. Here, we performed in-depth cross-linking of the E. coli ribosome using the amine-reactive cross-linker disuccinimidyl diacetic urea (DSAU). We analyzed 143 E. coli ribosomal structures, mapping a total of 10,771 intramolecular distances for 126 cross-link-pairs and 3,405 intermolecular distances for 97 protein pairs. Remarkably, 44% of intermolecular cross-links covered regions that have not been resolved in any high-resolution E. coli ribosome structure and point to a plasticity of cross-linked regions. We systematically characterized all cross-links and discovered flexible regions, conformational changes, and stoichiometric variations in bound ribosomal proteins, and ultimately remodeled 2,057 residues (15,794 atoms) in total. Our working model explains more than 95% of all cross-links, resulting in an optimized E. coli ribosome structure based on the cross-linking data obtained. Our study might serve as benchmark for conducting biochemical experiments on newly modeled protein regions, guided by XL-MS. Data are available via ProteomeXchange with identifier PXD018935.
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Affiliation(s)
- Christian Tüting
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany
| | - Claudio Iacobucci
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany
- Corporate Preclinical R&D, Analytics and Early Formulations Department, CHIESI FARMACEUTICI S.P.A., Via Palermo 26/A, 43122, Parma, Italy
| | - Christian H Ihling
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany
- Center for Structural Mass Spectrometry, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany
| | - Panagiotis L Kastritis
- Interdisciplinary Research Center HALOmem, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany.
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120, Halle/Saale, Germany.
- Biozentrum, Martin Luther University Halle-Wittenberg, Weinbergweg 22, 06120, Halle/Saale, Germany.
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of Pharmacy, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany.
- Center for Structural Mass Spectrometry, Charles Tanford Protein Center, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3a, 06120, Halle/Saale, Germany.
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Progression from remodeling to hibernation of ribosomes in zinc-starved mycobacteria. Proc Natl Acad Sci U S A 2020; 117:19528-19537. [PMID: 32723821 PMCID: PMC7431043 DOI: 10.1073/pnas.2013409117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We previously reported that hibernation of 70S ribosomes in mycobacteria is induced as a response to zinc starvation. Because zinc limitation also induces ribosome remodeling, our findings raise questions about the conditions for ribosome remodeling and hibernation. Here, we show that the two processes are induced at different concentrations of zinc and that the caseinolytic protease system plays a crucial role in zinc-dependent inhibition of hibernation during remodeling. The findings offer insights into the molecular pathway underlying the transition from remodeling of ribosomes to hibernation in response to progressive zinc depletion in mycobacteria. This study is also a demonstration of reactivation of hibernating ribosomes by zinc. Finally, this study correlates ribosome hibernation with streptomycin tolerance in Mycobacterium tuberculosis during infection. Zinc starvation in mycobacteria leads to remodeling of ribosomes, in which multiple ribosomal (r-) proteins containing the zinc-binding CXXC motif are replaced by their motif-free paralogues, collectively called C− r-proteins. We previously reported that the 70S C− ribosome is exclusively targeted for hibernation by mycobacterial-specific protein Y (Mpy), which binds to the decoding center and stabilizes the ribosome in an inactive and drug-resistant state. In this study, we delineate the conditions for ribosome remodeling and hibernation and provide further insight into how zinc depletion induces Mpy recruitment to C− ribosomes. Specifically, we show that ribosome hibernation in a batch culture is induced at an approximately two-fold lower cellular zinc concentration than remodeling. We further identify a growth phase in which the C− ribosome remains active, while its hibernation is inhibited by the caseinolytic protease (Clp) system in a zinc-dependent manner. The Clp protease system destabilizes a zinc-bound form of Mpy recruitment factor (Mrf), which is stabilized upon further depletion of zinc, presumably in a zinc-free form. Stabilized Mrf binds to the 30S subunit and recruits Mpy to the ribosome. Replenishment of zinc to cells harboring hibernating ribosomes restores Mrf instability and dissociates Mpy from the ribosome. Finally, we demonstrate zinc-responsive binding of Mpy to ribosomes in Mycobacterium tuberculosis (Mtb) and show Mpy-dependent antibiotic tolerance of Mtb in mouse lungs. Together, we propose that ribosome hibernation is a specific and conserved response to zinc depletion in both environmental and pathogenic mycobacteria.
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31
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Wells JN, Buschauer R, Mackens-Kiani T, Best K, Kratzat H, Berninghausen O, Becker T, Gilbert W, Cheng J, Beckmann R. Structure and function of yeast Lso2 and human CCDC124 bound to hibernating ribosomes. PLoS Biol 2020; 18:e3000780. [PMID: 32687489 PMCID: PMC7392345 DOI: 10.1371/journal.pbio.3000780] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/30/2020] [Accepted: 07/01/2020] [Indexed: 12/20/2022] Open
Abstract
Cells adjust to nutrient deprivation by reversible translational shutdown. This is accompanied by maintaining inactive ribosomes in a hibernation state, in which they are bound by proteins with inhibitory and protective functions. In eukaryotes, such a function was attributed to suppressor of target of Myb protein 1 (Stm1; SERPINE1 mRNA-binding protein 1 [SERBP1] in mammals), and recently, late-annotated short open reading frame 2 (Lso2; coiled-coil domain containing short open reading frame 124 [CCDC124] in mammals) was found to be involved in translational recovery after starvation from stationary phase. Here, we present cryo-electron microscopy (cryo-EM) structures of translationally inactive yeast and human ribosomes. We found Lso2/CCDC124 accumulating on idle ribosomes in the nonrotated state, in contrast to Stm1/SERBP1-bound ribosomes, which display a rotated state. Lso2/CCDC124 bridges the decoding sites of the small with the GTPase activating center (GAC) of the large subunit. This position allows accommodation of the duplication of multilocus region 34 protein (Dom34)-dependent ribosome recycling system, which splits Lso2-containing, but not Stm1-containing, ribosomes. We propose a model in which Lso2 facilitates rapid translation reactivation by stabilizing the recycling-competent state of inactive ribosomes.
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Affiliation(s)
- Jennifer N. Wells
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Robert Buschauer
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Timur Mackens-Kiani
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Katharina Best
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Hanna Kratzat
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Otto Berninghausen
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Thomas Becker
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Wendy Gilbert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, United States of America
| | - Jingdong Cheng
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
| | - Roland Beckmann
- Gene Center and Center for Integrated Protein Science Munich, Department of Biochemistry, University of Munich, Munich, Germany
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Sas-Chen A, Thomas JM, Matzov D, Taoka M, Nance KD, Nir R, Bryson KM, Shachar R, Liman GLS, Burkhart BW, Gamage ST, Nobe Y, Briney CA, Levy MJ, Fuchs RT, Robb GB, Hartmann J, Sharma S, Lin Q, Florens L, Washburn MP, Isobe T, Santangelo TJ, Shalev-Benami M, Meier JL, Schwartz S. Dynamic RNA acetylation revealed by quantitative cross-evolutionary mapping. Nature 2020; 583:638-643. [PMID: 32555463 PMCID: PMC8130014 DOI: 10.1038/s41586-020-2418-2] [Citation(s) in RCA: 154] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 03/26/2020] [Indexed: 12/14/2022]
Abstract
N4-acetylcytidine (ac4C) is an ancient and highly conserved RNA modification that is present on tRNA and rRNA and has recently been investigated in eukaryotic mRNA1-3. However, the distribution, dynamics and functions of cytidine acetylation have yet to be fully elucidated. Here we report ac4C-seq, a chemical genomic method for the transcriptome-wide quantitative mapping of ac4C at single-nucleotide resolution. In human and yeast mRNAs, ac4C sites are not detected but can be induced-at a conserved sequence motif-via the ectopic overexpression of eukaryotic acetyltransferase complexes. By contrast, cross-evolutionary profiling revealed unprecedented levels of ac4C across hundreds of residues in rRNA, tRNA, non-coding RNA and mRNA from hyperthermophilic archaea. Ac4C is markedly induced in response to increases in temperature, and acetyltransferase-deficient archaeal strains exhibit temperature-dependent growth defects. Visualization of wild-type and acetyltransferase-deficient archaeal ribosomes by cryo-electron microscopy provided structural insights into the temperature-dependent distribution of ac4C and its potential thermoadaptive role. Our studies quantitatively define the ac4C landscape, providing a technical and conceptual foundation for elucidating the role of this modification in biology and disease4-6.
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Affiliation(s)
- Aldema Sas-Chen
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Justin M Thomas
- National Cancer Institute, National Institutes of Health, Frederick, MD, USA
| | - Donna Matzov
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Masato Taoka
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | - Kellie D Nance
- National Cancer Institute, National Institutes of Health, Frederick, MD, USA
| | - Ronit Nir
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Keri M Bryson
- National Cancer Institute, National Institutes of Health, Frederick, MD, USA
| | - Ran Shachar
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Geraldy L S Liman
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Brett W Burkhart
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | | | - Yuko Nobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | - Chloe A Briney
- National Cancer Institute, National Institutes of Health, Frederick, MD, USA
| | | | - Ryan T Fuchs
- RNA Research Division, New England Biolabs, Inc, Ipswich, MA, USA
| | - G Brett Robb
- RNA Research Division, New England Biolabs, Inc, Ipswich, MA, USA
| | - Jesse Hartmann
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Sunny Sharma
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, NJ, USA
| | - Qishan Lin
- RNA Epitranscriptomics and Proteomics Resource, University at Albany, Albany, NY, USA
| | | | | | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Tokyo, Japan
| | - Thomas J Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Moran Shalev-Benami
- Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.
| | - Jordan L Meier
- National Cancer Institute, National Institutes of Health, Frederick, MD, USA.
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
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Ribosome Dimerization Protects the Small Subunit. J Bacteriol 2020; 202:JB.00009-20. [PMID: 32123037 PMCID: PMC7186458 DOI: 10.1128/jb.00009-20] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/25/2020] [Indexed: 01/21/2023] Open
Abstract
When nutrients become scarce, bacteria can enter an extended state of quiescence. A major challenge of this state is how to preserve ribosomes for the return to favorable conditions. Here, we show that the ribosome dimerization protein hibernation-promoting factor (HPF) functions to protect essential ribosomal proteins. Ribosomes isolated from strains lacking HPF (Δhpf) or encoding a mutant allele of HPF that binds the ribosome but does not mediate dimerization were substantially depleted of the small subunit proteins S2 and S3. Strikingly, these proteins are located directly at the ribosome dimer interface. We used single-particle cryo-electron microscopy (cryo-EM) to further characterize these ribosomes and observed that a high percentage of ribosomes were missing S2, S3, or both. These data support a model in which the ribosome dimerization activity of HPF evolved to protect labile proteins that are essential for ribosome function. HPF is almost universally conserved in bacteria, and HPF deletions in diverse species exhibit decreased viability during starvation. Our data provide mechanistic insight into this phenotype and establish a mechanism for how HPF protects ribosomes during quiescence.IMPORTANCE The formation of ribosome dimers during periods of dormancy is widespread among bacteria. Dimerization is typically mediated by a single protein, hibernation-promoting factor (HPF). Bacteria lacking HPF exhibit strong defects in viability and pathogenesis and, in some species, extreme loss of rRNA. The mechanistic basis of these phenotypes has not been determined. Here, we report that HPF from the Gram-positive bacterium Bacillus subtilis preserves ribosomes by preventing the loss of essential ribosomal proteins at the dimer interface. This protection may explain phenotypes associated with the loss of HPF, since ribosome protection would aid survival during nutrient limitation and impart a strong selective advantage when the bacterial cell rapidly reinitiates growth in the presence of sufficient nutrients.
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34
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Mechanism of ribosome shutdown by RsfS in Staphylococcus aureus revealed by integrative structural biology approach. Nat Commun 2020; 11:1656. [PMID: 32245971 PMCID: PMC7125091 DOI: 10.1038/s41467-020-15517-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 03/05/2020] [Indexed: 11/08/2022] Open
Abstract
For the sake of energy preservation, bacteria, upon transition to stationary phase, tone down their protein synthesis. This process is favored by the reversible binding of small stress-induced proteins to the ribosome to prevent unnecessary translation. One example is the conserved bacterial ribosome silencing factor (RsfS) that binds to uL14 protein onto the large ribosomal subunit and prevents its association with the small subunit. Here we describe the binding mode of Staphylococcus aureus RsfS to the large ribosomal subunit and present a 3.2 Å resolution cryo-EM reconstruction of the 50S-RsfS complex together with the crystal structure of uL14-RsfS complex solved at 2.3 Å resolution. The understanding of the detailed landscape of RsfS-uL14 interactions within the ribosome shed light on the mechanism of ribosome shutdown in the human pathogen S. aureus and might deliver a novel target for pharmacological drug development and treatment of bacterial infections.
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35
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Basu A, Shields KE, Yap MNF. The hibernating 100S complex is a target of ribosome-recycling factor and elongation factor G in Staphylococcus aureus. J Biol Chem 2020; 295:6053-6063. [PMID: 32209660 PMCID: PMC7196661 DOI: 10.1074/jbc.ra119.012307] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 03/18/2020] [Indexed: 12/24/2022] Open
Abstract
The formation of translationally inactive 70S dimers (called 100S ribosomes) by hibernation-promoting factor is a widespread survival strategy among bacteria. Ribosome dimerization is thought to be reversible, with the dissociation of the 100S complexes enabling ribosome recycling for participation in new rounds of translation. The precise pathway of 100S ribosome recycling has been unclear. We previously found that the heat-shock GTPase HflX in the human pathogen Staphylococcus aureus is a minor disassembly factor. Cells lacking hflX do not accumulate 100S ribosomes unless they are subjected to heat exposure, suggesting the existence of an alternative pathway during nonstressed conditions. Here, we provide biochemical and genetic evidence that two essential translation factors, ribosome-recycling factor (RRF) and GTPase elongation factor G (EF-G), synergistically split 100S ribosomes in a GTP-dependent but tRNA translocation-independent manner. We found that although HflX and the RRF/EF-G pair are functionally interchangeable, HflX is expressed at low levels and is dispensable under normal growth conditions. The bacterial RRF/EF-G pair was previously known to target only the post-termination 70S complexes; our results reveal a new role in the reversal of ribosome hibernation that is intimately linked to bacterial pathogenesis, persister formation, stress responses, and ribosome integrity.
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Affiliation(s)
- Arnab Basu
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104
| | - Kathryn E Shields
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104
| | - Mee-Ngan F Yap
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, Missouri 63104; Department of Microbiology-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
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Trösch R, Willmund F. The conserved theme of ribosome hibernation: from bacteria to chloroplasts of plants. Biol Chem 2020; 400:879-893. [PMID: 30653464 DOI: 10.1515/hsz-2018-0436] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 01/03/2019] [Indexed: 12/21/2022]
Abstract
Cells are highly adaptive systems that respond and adapt to changing environmental conditions such as temperature fluctuations or altered nutrient availability. Such acclimation processes involve reprogramming of the cellular gene expression profile, tuning of protein synthesis, remodeling of metabolic pathways and morphological changes of the cell shape. Nutrient starvation can lead to limited energy supply and consequently, remodeling of protein synthesis is one of the key steps of regulation since the translation of the genetic code into functional polypeptides may consume up to 40% of a cell's energy during proliferation. In eukaryotic cells, downregulation of protein synthesis during stress is mainly mediated by modification of the translation initiation factors. Prokaryotic cells suppress protein synthesis by the active formation of dimeric so-called 'hibernating' 100S ribosome complexes. Such a transition involves a number of proteins which are found in various forms in prokaryotes but also in chloroplasts of plants. Here, we review the current understanding of these hibernation factors and elaborate conserved principles which are shared between species.
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Affiliation(s)
- Raphael Trösch
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
| | - Felix Willmund
- Department of Biology, Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Straße 23, D-67663 Kaiserslautern, Germany
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Morgan CE, Huang W, Rudin SD, Taylor DJ, Kirby JE, Bonomo RA, Yu EW. Cryo-electron Microscopy Structure of the Acinetobacter baumannii 70S Ribosome and Implications for New Antibiotic Development. mBio 2020; 11:e03117-19. [PMID: 31964740 PMCID: PMC6974574 DOI: 10.1128/mbio.03117-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/02/2019] [Indexed: 01/11/2023] Open
Abstract
Antimicrobial resistance is a major health threat as it limits treatment options for infection. At the forefront of this serious issue is Acinetobacter baumannii, a Gram-negative opportunistic pathogen that exhibits the remarkable ability to resist antibiotics through multiple mechanisms. As bacterial ribosomes represent a target for multiple distinct classes of existing antimicrobial agents, we here use single-particle cryo-electron microscopy (cryo-EM) to elucidate five different structural states of the A. baumannii ribosome, including the 70S, 50S, and 30S forms. We also determined interparticle motions of the 70S ribosome in different tRNA bound states using three-dimensional (3D) variability analysis. Together, our structural data further our understanding of the ribosome from A. baumannii and other Gram-negative pathogens and will enable structure-based drug discovery to combat antibiotic-resistant bacterial infections.IMPORTANCEAcinetobacter baumannii is a severe nosocomial threat largely due to its intrinsic antibiotic resistance and remarkable ability to acquire new resistance determinants. The bacterial ribosome serves as a major target for modern antibiotics and the design of new therapeutics. Here, we present cryo-EM structures of the A. baumannii 70S ribosome, revealing several unique species-specific structural features that may facilitate future drug development to combat this recalcitrant bacterial pathogen.
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Affiliation(s)
- Christopher E Morgan
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Wei Huang
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Susan D Rudin
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Derek J Taylor
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - James E Kirby
- Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
- Harvard Medical School, Boston, Massachusetts, USA
| | - Robert A Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Case Center for Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology, Cleveland, Ohio, USA
| | - Edward W Yu
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
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38
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Dimerization of long hibernation promoting factor from Staphylococcus aureus: Structural analysis and biochemical characterization. J Struct Biol 2020; 209:107408. [DOI: 10.1016/j.jsb.2019.107408] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/22/2019] [Accepted: 10/24/2019] [Indexed: 11/22/2022]
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Kushwaha AK, Bhushan S. Unique structural features of the Mycobacterium ribosome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2019; 152:15-24. [PMID: 31858996 DOI: 10.1016/j.pbiomolbio.2019.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/03/2019] [Accepted: 12/09/2019] [Indexed: 12/16/2022]
Abstract
Protein synthesis in all the living cells is mediated by a large protein-RNA complex called the ribosome. These macromolecular complexes can range from 2.5 (prokaryotes) to 4.2 MDa. (eukaryotes) in size and undergo various conformational transitions during protein synthesis to translate the genetic code into the nascent polypeptide chains. Recent advances in cryo-electron microscopy (cryo-EM) and image processing methods have provided numerous detailed structures of ribosomes from diverse sources and in different conformational states resolved to near-atomic resolutions. These structures have not only helped in better understanding of the translational mechanism but also revealed species-specific variations or adaptations in the ribosome structures. Structural investigations of the ribosomes from Mycobacterium smegmatis (Msm) and its closely related pathogenic Mycobacterium tuberculosis (Mtb) lead to the identification of two additional ribosomal proteins named as bS22 and bL37 and several unique extensions in ribosomal-protein and ribosomal-RNA. Hibernation Promoting Factor (HPF) bound structure of Msm ribosome, termed as the hibernating ribosome, possibly indicates a new mechanism of ribosome protection during dormancy. These studies enabled the identification of the mycobacteria-specific ribosomal features and provides an opportunity to understand their function and target them for further drug-discovery purposes. Here we review the unique structural features identified in Msm ribosome and their possible implications in comparison to a well-studied Escherichia coli (Ec) ribosome.
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Affiliation(s)
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, Singapore; NTU Institute of Structural Biology, Nanyang Technological University, Singapore.
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40
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Wilkinson ME, Kumar A, Casañal A. Methods for merging data sets in electron cryo-microscopy. Acta Crystallogr D Struct Biol 2019; 75:782-791. [PMID: 31478901 PMCID: PMC6719665 DOI: 10.1107/s2059798319010519] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 07/23/2019] [Indexed: 11/26/2022] Open
Abstract
Recent developments have resulted in electron cryo-microscopy (cryo-EM) becoming a useful tool for the structure determination of biological macromolecules. For samples containing inherent flexibility, heterogeneity or preferred orientation, the collection of extensive cryo-EM data using several conditions and microscopes is often required. In such a scenario, merging cryo-EM data sets is advantageous because it allows improved three-dimensional reconstructions to be obtained. Since data sets are not always collected with the same pixel size, merging data can be challenging. Here, two methods to combine cryo-EM data are described. Both involve the calculation of a rescaling factor from independent data sets. The effects of errors in the scaling factor on the results of data merging are also estimated. The methods described here provide a guideline for cryo-EM users who wish to combine data sets from the same type of microscope and detector.
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Affiliation(s)
- Max E. Wilkinson
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Ananthanarayanan Kumar
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Ana Casañal
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
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41
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Sawyer EB, Grabowska AD, Cortes T. Translational regulation in mycobacteria and its implications for pathogenicity. Nucleic Acids Res 2019; 46:6950-6961. [PMID: 29947784 PMCID: PMC6101614 DOI: 10.1093/nar/gky574] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 06/14/2018] [Indexed: 01/13/2023] Open
Abstract
Protein synthesis is a fundamental requirement of all cells for survival and replication. To date, vast numbers of genetic and biochemical studies have been performed to address the mechanisms of translation and its regulation in Escherichia coli, but only a limited number of studies have investigated these processes in other bacteria, particularly in slow growing bacteria like Mycobacterium tuberculosis, the causative agent of human tuberculosis. In this Review, we highlight important differences in the translational machinery of M. tuberculosis compared with E. coli, specifically the presence of two additional proteins and subunit stabilizing elements such as the B9 bridge. We also consider the role of leaderless translation in the ability of M. tuberculosis to establish latent infection and look at the experimental evidence that translational regulatory mechanisms operate in mycobacteria during stress adaptation, particularly focussing on differences in toxin-antitoxin systems between E. coli and M. tuberculosis and on the role of tuneable translational fidelity in conferring phenotypic antibiotic resistance. Finally, we consider the implications of these differences in the context of the biological adaptation of M. tuberculosis and discuss how these regulatory mechanisms could aid in the development of novel therapeutics for tuberculosis.
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Affiliation(s)
- Elizabeth B Sawyer
- Pathogen Molecular Biology Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,TB Centre, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Anna D Grabowska
- Pathogen Molecular Biology Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,TB Centre, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Teresa Cortes
- Pathogen Molecular Biology Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.,TB Centre, London School of Hygiene & Tropical Medicine, Keppel Street, London WC1E 7HT, UK
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42
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Matzov D, Bashan A, Yap MNF, Yonath A. Stress response as implemented by hibernating ribosomes: a structural overview. FEBS J 2019; 286:3558-3565. [PMID: 31230411 PMCID: PMC6746590 DOI: 10.1111/febs.14968] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 05/14/2019] [Accepted: 06/20/2019] [Indexed: 02/07/2023]
Abstract
Protein synthesis is one of the most energy demanding cellular processes. The ability to regulate protein synthesis is essential for cells under normal as well as stress conditions, such as nutrient deficiencies. One mechanism for protein synthesis suppression is the dimerization of ribosomes into hibernation complexes. In most cells, this process is promoted by the hibernating promoting factor (HPF) and in a small group of Gram-negative bacteria (γ-proteobacteria), the dimer formation is induced by a shorter version of HPF (HPFshort ) and by an additional protein, the ribosome modulation factor. In most bacteria, the product of this process is the 100S ribosome complex. Recent advances in cryogenic electron microscopy methods resulted in an abundance of detailed structures of near atomic resolutions 100S complexes that allow for a better understanding of the dimerization process and the way it inhibits protein synthesis. As ribosomal dimerization is vital for cell survival, this process is an attractive target for the development of novel antimicrobial substances that might inhibit or stabilize the complex formation. As different dimerization processes exist among bacteria, including pathogens, this process may provide the basis for species-specific design of antimicrobial agents. Here, we review in detail the various dimerization mechanisms and discuss how they affect the overall dimer structures of the bacterial ribosomes.
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Affiliation(s)
- Donna Matzov
- Structural Biology, Weizmann Institute. Rehovot, Israel
| | - Anat Bashan
- Structural Biology, Weizmann Institute. Rehovot, Israel
| | - Mee-Ngan F Yap
- Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO, USA.,Microbiology and Immunology, Northwestern University, Chicago, IL, USA
| | - Ada Yonath
- Structural Biology, Weizmann Institute. Rehovot, Israel
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43
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Rugen N, Straube H, Franken LE, Braun HP, Eubel H. Complexome Profiling Reveals Association of PPR Proteins with Ribosomes in the Mitochondria of Plants. Mol Cell Proteomics 2019; 18:1345-1362. [PMID: 31023727 PMCID: PMC6601216 DOI: 10.1074/mcp.ra119.001396] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/12/2019] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial transcripts are subject to a wealth of processing mechanisms including cis- and trans-splicing events, as well as base modifications (RNA editing). Hundreds of proteins are required for these processes in plant mitochondria, many of which belong to the pentatricopeptide repeat (PPR) protein superfamily. The structure, localization, and function of these proteins is only poorly understood. Here we present evidence that several PPR proteins are bound to mitoribosomes in plants. A novel complexome profiling strategy in combination with chemical crosslinking has been employed to systematically define the protein constituents of the large and the small ribosomal subunits in the mitochondria of plants. We identified more than 80 ribosomal proteins, which include several PPR proteins and other non-conventional ribosomal proteins. These findings reveal a potential coupling of transcriptional and translational events in the mitochondria of plants. Furthermore, the data indicate an extremely high molecular mass of the "small" subunit, even exceeding that of the "large" subunit.
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Affiliation(s)
- Nils Rugen
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Henryk Straube
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Linda E Franken
- §Heinrich Pette Institute, Leibniz Institute for Experimental Virology - Centre for Structural Systems Biology, Notkestraβe 85, 22607 Hamburg, Germany
| | - Hans-Peter Braun
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Holger Eubel
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany;.
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44
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Olson WK, Li S, Kaukonen T, Colasanti AV, Xin Y, Lu XJ. Effects of Noncanonical Base Pairing on RNA Folding: Structural Context and Spatial Arrangements of G·A Pairs. Biochemistry 2019; 58:2474-2487. [PMID: 31008589 PMCID: PMC6729125 DOI: 10.1021/acs.biochem.9b00122] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Noncanonical base pairs play important roles in assembling the three-dimensional structures critical to the diverse functions of RNA. These associations contribute to the looped segments that intersperse the canonical double-helical elements within folded, globular RNA molecules. They stitch together various structural elements, serve as recognition elements for other molecules, and act as sites of intrinsic stiffness or deformability. This work takes advantage of new software (DSSR) designed to streamline the analysis and annotation of RNA three-dimensional structures. The multiscale structural information gathered for individual molecules, combined with the growing number of unique, well-resolved RNA structures, makes it possible to examine the collective features deeply and to uncover previously unrecognized patterns of chain organization. Here we focus on a subset of noncanonical base pairs involving guanine and adenine and the links between their modes of association, secondary structural context, and contributions to tertiary folding. The rigorous descriptions of base-pair geometry that we employ facilitate characterization of recurrent geometric motifs and the structural settings in which these arrangements occur. Moreover, the numerical parameters hint at the natural motions of the interacting bases and the pathways likely to connect different spatial forms. We draw attention to higher-order multiplexes involving two or more G·A pairs and the roles these associations appear to play in bridging different secondary structural units. The collective data reveal pairing propensities in base organization, secondary structural context, and deformability and serve as a starting point for further multiscale investigations and/or simulations of RNA folding.
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Affiliation(s)
- Wilma K. Olson
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Shuxiang Li
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Thomas Kaukonen
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Andrew V. Colasanti
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Yurong Xin
- Department of Chemistry & Chemical Biology and Center for Quantitative Biology, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Xiang-Jun Lu
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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45
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Rast A, Schaffer M, Albert S, Wan W, Pfeffer S, Beck F, Plitzko JM, Nickelsen J, Engel BD. Biogenic regions of cyanobacterial thylakoids form contact sites with the plasma membrane. NATURE PLANTS 2019; 5:436-446. [PMID: 30962530 DOI: 10.1038/s41477-019-0399-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 03/04/2019] [Indexed: 05/20/2023]
Abstract
Little is known about how the photosynthetic machinery is arranged in time and space during the biogenesis of thylakoid membranes. Using in situ cryo-electron tomography to image the three-dimensional architecture of the cyanobacterium Synechocystis, we observed that the tips of multiple thylakoids merge to form a substructure called the 'convergence membrane'. This high-curvature membrane comes into close contact with the plasma membrane at discrete sites. We generated subtomogram averages of 70S ribosomes and array-forming phycobilisomes, then mapped these structures onto the native membrane architecture as markers for protein synthesis and photosynthesis, respectively. This molecular localization identified two distinct biogenic regions in the thylakoid network: thylakoids facing the cytosolic interior of the cell that were associated with both marker complexes, and convergence membranes that were decorated by ribosomes but not phycobilisomes. We propose that the convergence membranes perform a specialized biogenic function, coupling the synthesis of thylakoid proteins with the integration of cofactors from the plasma membrane and the periplasmic space.
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Affiliation(s)
- Anna Rast
- Department of Molecular Plant Sciences, Ludwig-Maximilians-University Munich, Martinsried, Germany
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Miroslava Schaffer
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Sahradha Albert
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - William Wan
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Stefan Pfeffer
- Center for Molecular Biology, University of Heidelberg, Heidelberg, Germany
| | - Florian Beck
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jürgen M Plitzko
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Jörg Nickelsen
- Department of Molecular Plant Sciences, Ludwig-Maximilians-University Munich, Martinsried, Germany.
| | - Benjamin D Engel
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried, Germany.
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46
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Zinc depletion does not necessarily induce ribosome hibernation in mycobacteria. Proc Natl Acad Sci U S A 2019; 116:2395-2397. [PMID: 30683730 DOI: 10.1073/pnas.1817490116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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47
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Bacterial ribosome heterogeneity: Changes in ribosomal protein composition during transition into stationary growth phase. Biochimie 2019; 156:169-180. [DOI: 10.1016/j.biochi.2018.10.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 10/18/2018] [Indexed: 12/11/2022]
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48
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Rakesh KP, Marichannegowda MH, Srivastava S, Chen X, Long S, Karthik CS, Mallu P, Qin HL. Combating a Master Manipulator: Staphylococcus aureus Immunomodulatory Molecules as Targets for Combinatorial Drug Discovery. ACS COMBINATORIAL SCIENCE 2018; 20:681-693. [PMID: 30372025 DOI: 10.1021/acscombsci.8b00088] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is a bacterial pathogen that can cause significant disease burden and mortality by counteracting host defenses through producing virulence factors to survive the immune responses evoked by infection. This emerging drug-resistant pathogen has led to a decline in the efficacy of traditional antimicrobial therapy. To combat these threats, precision antimicrobial therapeutics have been created to target key virulence determinants of specific pathogens. Here we review the benefits of, progresses in, and roadblocks to the development of precision antimicrobial therapeutics using combinatorial chemistry.
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Affiliation(s)
- Kadalipura P. Rakesh
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
| | | | - Shobhith Srivastava
- Department of Pharmacology and Therapeutics, King George’s Medical University, Chowk, Lucknow 226003, India
| | - Xing Chen
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
| | - Sihui Long
- Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, Hubei, China
| | - Chimatahalli S. Karthik
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, Mysuru 570006, Karnataka, India
| | - Putswamappa Mallu
- Department of Chemistry, Sri Jayachamarajendra College of Engineering, Mysuru 570006, Karnataka, India
| | - Hua-Li Qin
- Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, Hubei, P. R. China
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49
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Thermal and Nutritional Regulation of Ribosome Hibernation in Staphylococcus aureus. J Bacteriol 2018; 200:JB.00426-18. [PMID: 30297357 PMCID: PMC6256015 DOI: 10.1128/jb.00426-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 09/25/2018] [Indexed: 12/13/2022] Open
Abstract
The dimerization of 70S ribosomes (100S complex) plays an important role in translational regulation and infectivity of the major human pathogen Staphylococcus aureus. Although the dimerizing factor HPF has been characterized biochemically, the pathways that regulate 100S ribosome abundance remain elusive. We identified a metabolite- and nutrient-sensing transcription factor, CodY, that serves both as an activator and a repressor of hpf expression in nutrient- and temperature-dependent manners. Furthermore, CodY-mediated activation of hpf masks a secondary hpf transcript derived from a general stress response SigB promoter. CodY and SigB regulate a repertoire of virulence genes. The unexpected link between ribosome homeostasis and the two master virulence regulators provides new opportunities for alternative druggable sites. The translationally silent 100S ribosome is a poorly understood form of the dimeric 70S complex that is ubiquitously found in all bacterial phyla. The elimination of the hibernating 100S ribosome leads to translational derepression, ribosome instability, antibiotic sensitivity, and biofilm defects in some bacteria. In Firmicutes, such as the opportunistic pathogen Staphylococcus aureus, a 190-amino acid protein called hibernating-promoting factor (HPF) dimerizes and conjoins two 70S ribosomes through a direct interaction between the HPF homodimer, with each HPF monomer tethered on an individual 70S complex. While the formation of the 100S ribosome in gammaproteobacteria and cyanobacteria is exclusively induced during postexponential growth phase and darkness, respectively, the 100S ribosomes in Firmicutes are constitutively produced from the lag-logarithmic phase through the post-stationary phase. Very little is known about the regulatory pathways that control hpf expression and 100S ribosome abundance. Here, we show that a general stress response (GSR) sigma factor (SigB) and a GTP-sensing transcription factor (CodY) integrate nutrient and thermal signals to regulate hpf synthesis in S. aureus, resulting in an enhanced virulence of the pathogen in a mouse model of septicemic infection. CodY-dependent regulation of hpf is strain specific. An epistasis analysis further demonstrated that CodY functions upstream of the GSR pathway in a condition-dependent manner. The results reveal an important link between S. aureus stress physiology, ribosome metabolism, and infection biology. IMPORTANCE The dimerization of 70S ribosomes (100S complex) plays an important role in translational regulation and infectivity of the major human pathogen Staphylococcus aureus. Although the dimerizing factor HPF has been characterized biochemically, the pathways that regulate 100S ribosome abundance remain elusive. We identified a metabolite- and nutrient-sensing transcription factor, CodY, that serves both as an activator and a repressor of hpf expression in nutrient- and temperature-dependent manners. Furthermore, CodY-mediated activation of hpf masks a secondary hpf transcript derived from a general stress response SigB promoter. CodY and SigB regulate a repertoire of virulence genes. The unexpected link between ribosome homeostasis and the two master virulence regulators provides new opportunities for alternative druggable sites.
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Structural modules of the stress-induced protein HflX: an outlook on its evolution and biological role. Curr Genet 2018; 65:363-370. [PMID: 30448945 DOI: 10.1007/s00294-018-0905-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 11/05/2018] [Accepted: 11/13/2018] [Indexed: 12/23/2022]
Abstract
Multifunctional proteins often show modular structures. A functional domain and the structural modules within the domain show evolutionary conservation of their spatial arrangement since that gives the protein its functionality. However, the question remains as to how members of different domains of life (Archaea, Bacteria, Eukarya), polish and perfect these modules within conserved multidomain proteins, to tailor functional proteins according to their specific requirements. In the quest for plausible answers to this question, we studied the bacterial protein HflX. HflX is a universally conserved member of the Obg-GTPase superfamily but its functional role in Archaea and Eukarya is barely known. It is a multidomain protein and possesses, in addition to its conserved GTPase domain, an ATP-binding N-terminal domain. It is involved in heat stress response in Escherichia coli and our laboratory recently identified an ATP-dependent RNA helicase activity of E. coli HflX, which is likely instrumental in rescuing ribosomes during heat stress. Because perception and response to stress is expected to be different in different life forms, the question is whether this activity is preserved in higher organisms or not. Thus, we explored the evolution pattern of different structural modules of HflX, with particular emphasis on the ATP-binding domain, to understand plausible biological role of HflX in other forms of life. Our analyses indicate that, while the evolutionary pattern of the GTPase domain follows a conserved phylogeny, conservation of the ATP-binding domain shows a complicated pattern. The limited analysis described here hints towards possible evolutionary adaptations and modifications of the domain, something which needs to be investigated in more depth in homologs from other life forms. Deciphering how nature 'tweaks' such modules, both structurally and functionally, may help in understanding the evolution of such proteins, and, on a large-scale, of stress-related proteins in general as well.
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