1
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Majumdar S, Kashyap A, Koripella RK, Sharma MR, Hurst-Hess K, Manjari SR, Banavali NK, Ghosh P, Agrawal RK. Drug resistance through ribosome splitting and rRNA disordering in mycobacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.13.598844. [PMID: 38915643 PMCID: PMC11195266 DOI: 10.1101/2024.06.13.598844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
HflX is known to rescue stalled ribosomes and is implicated in antibiotic resistance in several bacteria. Here we present several high-resolution cryo-EM structures of mycobacterial HflX in complex with the ribosome and its 50S subunit, with and without antibiotics. These structures reveal a distinct mechanism for HflX-mediated ribosome splitting and antibiotic resistance in mycobacteria. In addition to dissociating ribosome into two subunits, mycobacterial HflX mediates persistent disordering of multiple 23S rRNA helices to generate an inactive pool of 50S subunits. Mycobacterial HflX also acts as an anti-association factor by binding to pre-dissociated 50S subunits. A mycobacteria-specific insertion in HflX reaches further into the peptidyl transferase center. The position of this insertion overlaps with ribosome-bound macrolides or lincosamide class of antibiotics. The extended conformation of insertion seen in the absence of these antibiotics retracts and adjusts around the bound antibiotics instead of physically displacing them. It therefore likely imparts antibiotic resistance by sequestration of the antibiotic-bound inactive 50S subunits.
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Affiliation(s)
- Soneya Majumdar
- Division of Translational Medicine, New York State Department of Health, Albany, NY
| | - Amuliya Kashyap
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY
| | - Ravi K. Koripella
- Division of Translational Medicine, New York State Department of Health, Albany, NY
| | - Manjuli R. Sharma
- Division of Translational Medicine, New York State Department of Health, Albany, NY
| | - Kelley Hurst-Hess
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY
| | - Swati R. Manjari
- Division of Translational Medicine, New York State Department of Health, Albany, NY
| | - Nilesh K. Banavali
- Division of Translational Medicine, New York State Department of Health, Albany, NY
- Department of Biomedical Sciences, University at Albany, Albany, NY
| | - Pallavi Ghosh
- Division of Genetics, Wadsworth Center, New York State Department of Health, Albany, NY
- Department of Biomedical Sciences, University at Albany, Albany, NY
| | - Rajendra K. Agrawal
- Division of Translational Medicine, New York State Department of Health, Albany, NY
- Department of Biomedical Sciences, University at Albany, Albany, NY
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2
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Majumdar S, Deep A, Sharma MR, Canestrari J, Stone M, Smith C, Koripella RK, Keshavan P, Banavali NK, Wade JT, Gray TA, Derbyshire KM, Agrawal RK. The small mycobacterial ribosomal protein, bS22, modulates aminoglycoside accessibility to its 16S rRNA helix-44 binding site. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535098. [PMID: 37034768 PMCID: PMC10081302 DOI: 10.1101/2023.03.31.535098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Treatment of tuberculosis continues to be challenging due to the widespread latent form of the disease and the emergence of antibiotic-resistant strains of the pathogen, Mycobacterium tuberculosis. Bacterial ribosomes are a common and effective target for antibiotics. Several second line anti-tuberculosis drugs, e.g. kanamycin, amikacin, and capreomycin, target ribosomal RNA to inhibit protein synthesis. However, M. tuberculosis can acquire resistance to these drugs, emphasizing the need to identify new drug targets. Previous cryo-EM structures of the M. tuberculosis and M. smegmatis ribosomes identified two novel ribosomal proteins, bS22 and bL37, in the vicinity of two crucial drug-binding sites: the mRNA-decoding center on the small (30S), and the peptidyl-transferase center on the large (50S) ribosomal subunits, respectively. The functional significance of these two small proteins is unknown. In this study, we observe that an M. smegmatis strain lacking the bs22 gene shows enhanced susceptibility to kanamycin compared to the wild-type strain. Cryo-EM structures of the ribosomes lacking bS22 in the presence and absence of kanamycin suggest a direct role of bS22 in modulating the 16S rRNA kanamycin-binding site. Our structures suggest that amino-acid residue Lys-16 of bS22 interacts directly with the phosphate backbone of helix 44 of 16S rRNA to influence the micro-configuration of the kanamycin-binding pocket. Our analysis shows that similar interactions occur between eukaryotic homologues of bS22, and their corresponding rRNAs, pointing to a common mechanism of aminoglycoside resistance in higher organisms.
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Affiliation(s)
| | - Ayush Deep
- Division of Translational Medicine, Albany, NY 12237
| | | | - Jill Canestrari
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
| | - Melissa Stone
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
| | - Carol Smith
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
| | | | | | - Nilesh K Banavali
- Division of Translational Medicine, Albany, NY 12237
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12222
| | - Joseph T Wade
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12222
| | - Todd A Gray
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12222
| | - Keith M Derbyshire
- Division of Genetics, Wadsworth Center, New York State, Department of Health, Albany, NY 12237
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12222
| | - Rajendra K Agrawal
- Division of Translational Medicine, Albany, NY 12237
- Department of Biomedical Sciences, University at Albany, SUNY, Albany, NY 12222
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3
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Zhang W, Li Z, Sun Y, Cui P, Liang J, Xing Q, Wu J, Xu Y, Zhang W, Zhang Y, He L, Gao N. Cryo-EM structure of Mycobacterium tuberculosis 50S ribosomal subunit bound with clarithromycin reveals dynamic and specific interactions with macrolides. Emerg Microbes Infect 2021; 11:293-305. [PMID: 34935599 PMCID: PMC8786254 DOI: 10.1080/22221751.2021.2022439] [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] [Indexed: 11/30/2022]
Abstract
Tuberculosis (TB) is the leading infectious disease caused by Mycobacterium tuberculosis (Mtb). Clarithromycin (CTY), an analog of erythromycin (ERY), is more potent against multidrug-resistance (MDR) TB. ERY and CTY were previously reported to bind to the nascent polypeptide exit tunnel (NPET) near peptidyl transferase center (PTC), but the only available CTY structure in complex with D. radiodurans (Dra) ribosome could be misinterpreted due to resolution limitation. To date, the mechanism of specificity and efficacy of CTY for Mtb remains elusive since the Mtb ribosome-CTY complex structure is still unknown. Here, we employed new sample preparation methods and solved the Mtb ribosome-CTY complex structure at 3.3Å with cryo-EM technique, where the crucial gate site A2062 (E. coli numbering) is located at the CTY binding site within NPET. Two alternative conformations of A2062, a novel syn-conformation as well as a swayed conformation bound with water molecule at interface, may play a role in coordinating the binding of specific drug molecules. The previously overlooked C–H hydrogen bond (H-bond) and π interaction may collectively contribute to the enhanced binding affinity. Together, our structure data provide a structural basis for the dynamic binding as well as the specificity of CTY and explain of how a single methyl group in CTY improves its potency, which provides new evidence to reveal previously unclear mechanism of translational modulation for future drug design and anti-TB therapy. Furthermore, our sample preparation method may facilitate drug discovery based on the complexes with low water solubility drugs by cryo-EM technique.
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Affiliation(s)
- Wen Zhang
- Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - ZhiFei Li
- State Key Laboratory of Membrane Biology, National Biomedical Imaging Center, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, 100871, Beijing, China.,China National Center for Biotechnology Development. 10039, Beijing, China
| | - Yufan Sun
- Department of Medical Microbiology, Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Peng Cui
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Jianhua Liang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 102488, China
| | - Qinghe Xing
- Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Jing Wu
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yanhui Xu
- Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Wenhong Zhang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ying Zhang
- Department of Infectious Diseases, National Medical Center for Infectious Diseases, Shanghai Key Laboratory of Infectious Diseases and Biosafety Emergency Response, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai 200032, China.,State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China
| | - Lin He
- Institute of Biomedical Sciences, Fudan University, Shanghai 200032, China.,Bio-X Institute, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, National Biomedical Imaging Center, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, 100871, Beijing, China
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4
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Bendre AD, Peters PJ, Kumar J. Recent Insights into the Structure and Function of Mycobacterial Membrane Proteins Facilitated by Cryo-EM. J Membr Biol 2021; 254:321-341. [PMID: 33954837 PMCID: PMC8099146 DOI: 10.1007/s00232-021-00179-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Accepted: 03/23/2021] [Indexed: 12/26/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is one of the deadliest pathogens encountered by humanity. Over the decades, its characteristic membrane organization and composition have been understood. However, there is still limited structural information and mechanistic understanding of the constituent membrane proteins critical for drug discovery pipelines. Recent advances in single-particle cryo-electron microscopy and cryo-electron tomography have provided the much-needed impetus towards structure determination of several vital Mtb membrane proteins whose structures were inaccessible via X-ray crystallography and NMR. Important insights into membrane composition and organization have been gained via a combination of electron tomography and biochemical and biophysical assays. In addition, till the time of writing this review, 75 new structures of various Mtb proteins have been reported via single-particle cryo-EM. The information obtained from these structures has improved our understanding of the mechanisms of action of these proteins and the physiological pathways they are associated with. These structures have opened avenues for structure-based drug design and vaccine discovery programs that might help achieve global-TB control. This review describes the structural features of selected membrane proteins (type VII secretion systems, Rv1819c, Arabinosyltransferase, Fatty Acid Synthase, F-type ATP synthase, respiratory supercomplex, ClpP1P2 protease, ClpB disaggregase and SAM riboswitch), their involvement in physiological pathways, and possible use as a drug target. Tuberculosis is a deadly disease caused by Mycobacterium tuberculosis. The Cryo-EM and tomography have simplified the understanding of the mycobacterial membrane organization. Some proteins are located in the plasma membrane; some span the entire envelope, while some, like MspA, are located in the mycomembrane. Cryo-EM has made the study of such membrane proteins feasible.
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Affiliation(s)
- Ameya D Bendre
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University Campus, Ganeshkhind, Pune, Maharashtra, 411007, India
| | - Peter J Peters
- The Maastricht Multimodal Molecular Imaging Institute (M4I), Division of Nanoscopy, Maastricht University, Maastricht, The Netherlands
| | - Janesh Kumar
- Laboratory of Membrane Protein Biology, National Centre for Cell Science, NCCS Complex, S. P. Pune University Campus, Ganeshkhind, Pune, Maharashtra, 411007, India.
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5
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Jha V, Roy B, Jahagirdar D, McNutt ZA, Shatoff EA, Boleratz BL, Watkins DE, Bundschuh R, Basu K, Ortega J, Fredrick K. Structural basis of sequestration of the anti-Shine-Dalgarno sequence in the Bacteroidetes ribosome. Nucleic Acids Res 2021; 49:547-567. [PMID: 33330920 PMCID: PMC7797042 DOI: 10.1093/nar/gkaa1195] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 11/18/2020] [Accepted: 11/24/2020] [Indexed: 11/25/2022] Open
Abstract
Genomic studies have indicated that certain bacterial lineages such as the Bacteroidetes lack Shine-Dalgarno (SD) sequences, and yet with few exceptions ribosomes of these organisms carry the canonical anti-SD (ASD) sequence. Here, we show that ribosomes purified from Flavobacterium johnsoniae, a representative of the Bacteroidetes, fail to recognize the SD sequence of mRNA in vitro. A cryo-electron microscopy structure of the complete 70S ribosome from F. johnsoniae at 2.8 Å resolution reveals that the ASD is sequestered by ribosomal proteins bS21, bS18 and bS6, explaining the basis of ASD inhibition. The structure also uncovers a novel ribosomal protein—bL38. Remarkably, in F. johnsoniae and many other Flavobacteriia, the gene encoding bS21 contains a strong SD, unlike virtually all other genes. A subset of Flavobacteriia have an alternative ASD, and in these organisms the fully complementary sequence lies upstream of the bS21 gene, indicative of natural covariation. In other Bacteroidetes classes, strong SDs are frequently found upstream of the genes for bS21 and/or bS18. We propose that these SDs are used as regulatory elements, enabling bS21 and bS18 to translationally control their own production.
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Affiliation(s)
- Vikash Jha
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Bappaditya Roy
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - Dushyant Jahagirdar
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Zakkary A McNutt
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Elan A Shatoff
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA
| | - Bethany L Boleratz
- Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
| | - Dean E Watkins
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Ralf Bundschuh
- Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Department of Physics, The Ohio State University, Columbus, OH 43210, USA.,Department of Chemistry & Biochemistry, Division of Hematology, The Ohio State University, Columbus, OH 43210, USA
| | - Kaustuv Basu
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Joaquin Ortega
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada.,Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Kurt Fredrick
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.,Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.,Ohio State Biochemistry Program, The Ohio State University, Columbus, OH 43210, USA
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6
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Chang JY, Cui Z, Yang K, Huang J, Minary P, Zhang J. Hierarchical natural move Monte Carlo refines flexible RNA structures into cryo-EM densities. RNA (NEW YORK, N.Y.) 2020; 26:1755-1766. [PMID: 32826323 PMCID: PMC7668250 DOI: 10.1261/rna.071100.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/15/2020] [Indexed: 06/11/2023]
Abstract
Ribonucleic acids (RNAs) play essential roles in living cells. Many of them fold into defined three-dimensional (3D) structures to perform functions. Recent advances in single-particle cryo-electron microscopy (cryo-EM) have enabled structure determinations of RNA to atomic resolutions. However, most RNA molecules are structurally flexible, limiting the resolution of their structures solved by cryo-EM. In modeling these molecules, several computational methods are limited by the requirement of massive computational resources and/or the low efficiency in exploring large-scale structural variations. Here we use hierarchical natural move Monte Carlo (HNMMC), which takes advantage of collective motions for groups of nucleic acid residues, to refine RNA structures into their cryo-EM maps, preserving atomic details in the models. After validating the method on a simulated density map of tRNA, we applied it to objectively obtain the model of the folding intermediate for the specificity domain of ribonuclease P from Bacillus subtilis and refine a flexible ribosomal RNA (rRNA) expansion segment from the Mycobacterium tuberculosis (Mtb) ribosome in different conformational states. Finally, we used HNMMC to model atomic details and flexibility for two distinct conformations of the complete genomic RNA (gRNA) inside MS2, a single-stranded RNA virus, revealing multiple pathways for its capsid assembly.
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Affiliation(s)
- Jeng-Yih Chang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
- Center for Phage Technology, College Station, Texas 77843, USA
| | - Zhicheng Cui
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
- Center for Phage Technology, College Station, Texas 77843, USA
| | - Kailu Yang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
- Center for Phage Technology, College Station, Texas 77843, USA
| | - Jianhua Huang
- Department of Statistics, Texas A&M University, College Station, Texas 77843, USA
| | - Peter Minary
- Department of Computer Science, University of Oxford, Oxford OX1 3QD, United Kingdom
| | - Junjie Zhang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843, USA
- Center for Phage Technology, College Station, Texas 77843, USA
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7
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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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8
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Abstract
Many organisms, including bacteria, code for multiple paralogues of some ribosomal protein subunits. The relative contribution of these alternative subunits to ribosome function and protein synthesis is unknown and controversial. Many studies on alternative ribosomes have been confounded by isolation of alternative and canonical ribosomes from different strains or growth conditions, potentially confounding results. Here, we show that one form of alternative ribosome from Mycobacterium smegmatis has a distinct translational profile compared with canonical ribosomes purified from an identical cellular context. We also identify a role for alternative ribosomes in iron homeostasis. Given the prevalence of alternative ribosomal genes in diverse organisms, our study suggests that alternative ribosomes may represent a further layer of regulation of gene translation. Alternative ribosome subunit proteins are prevalent in the genomes of diverse bacterial species, but their functional significance is controversial. Attempts to study microbial ribosomal heterogeneity have mostly relied on comparing wild-type strains with mutants in which subunits have been deleted, but this approach does not allow direct comparison of alternate ribosome isoforms isolated from identical cellular contexts. Here, by simultaneously purifying canonical and alternative RpsR ribosomes from Mycobacterium smegmatis, we show that alternative ribosomes have distinct translational features compared with their canonical counterparts. Both alternative and canonical ribosomes actively take part in protein synthesis, although they translate a subset of genes with differential efficiency as measured by ribosome profiling. We also show that alternative ribosomes have a relative defect in initiation complex formation. Furthermore, a strain of M. smegmatis in which the alternative ribosome protein operon is deleted grows poorly in iron-depleted medium, uncovering a role for alternative ribosomes in iron homeostasis. Our work confirms the distinct and nonredundant contribution of alternative bacterial ribosomes for adaptation to hostile environments.
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9
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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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10
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Terwilliger TC, Adams PD, Afonine PV, Sobolev OV. A fully automatic method yielding initial models from high-resolution cryo-electron microscopy maps. Nat Methods 2018; 15:905-908. [PMID: 30377346 PMCID: PMC6214191 DOI: 10.1038/s41592-018-0173-1] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/06/2018] [Indexed: 01/31/2023]
Abstract
We report a fully automated procedure for the optimization and interpretation of reconstructions from cryo-electron microscopy (cryo-EM) data, available in Phenix as phenix.map_to_model. We applied our approach to 476 datasets with resolution of 4.5 Å or better, including reconstructions of 47 ribosomes and 32 other protein-RNA complexes. The median fraction of residues in the deposited structures reproduced automatically was 71% for reconstructions determined at resolutions of 3 Å or better and 47% for those at resolutions worse than 3 Å.
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Affiliation(s)
- Thomas C Terwilliger
- Los Alamos National Laboratory, Los Alamos, NM, USA.
- New Mexico Consortium, Los Alamos, NM, USA.
| | - Paul D Adams
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA, USA
| | - Pavel V Afonine
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Physics and International Centre for Quantum and Molecular Structures, Shanghai University, Shanghai, China
| | - Oleg V Sobolev
- Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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Mishra S, Ahmed T, Tyagi A, Shi J, Bhushan S. Structures of Mycobacterium smegmatis 70S ribosomes in complex with HPF, tmRNA, and P-tRNA. Sci Rep 2018; 8:13587. [PMID: 30206241 PMCID: PMC6133939 DOI: 10.1038/s41598-018-31850-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/23/2018] [Indexed: 11/09/2022] Open
Abstract
Ribosomes are the dynamic protein synthesis machineries of the cell. They may exist in different functional states in the cell. Therefore, it is essential to have structural information on these different functional states of ribosomes to understand their mechanism of action. Here, we present single particle cryo-EM reconstructions of the Mycobacterium smegmatis 70S ribosomes in the hibernating state (with HPF), trans-translating state (with tmRNA), and the P/P state (with P-tRNA) resolved to 4.1, 12.5, and 3.4 Å, respectively. A comparison of the P/P state with the hibernating state provides possible functional insights about the Mycobacteria-specific helix H54a rRNA segment. Interestingly, densities for all the four OB domains of bS1 protein is visible in the hibernating 70S ribosome displaying the molecular details of bS1-70S interactions. Our structural data shows a Mycobacteria-specific H54a-bS1 interaction which seems to prevent subunit dissociation and degradation during hibernation without the formation of 100S dimer. This indicates a new role of bS1 protein in 70S protection during hibernation in Mycobacteria in addition to its conserved function during translation initiation.
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MESH Headings
- Binding Sites
- Cryoelectron Microscopy
- Models, Molecular
- Mycobacterium smegmatis/genetics
- Mycobacterium smegmatis/metabolism
- Mycobacterium smegmatis/ultrastructure
- Nucleic Acid Conformation
- Protein Binding
- Protein Biosynthesis
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- RNA, Bacterial/chemistry
- RNA, Bacterial/genetics
- RNA, Bacterial/metabolism
- RNA, Ribosomal/chemistry
- RNA, Ribosomal/genetics
- RNA, Ribosomal/metabolism
- RNA, Transfer/chemistry
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Ribosomal Proteins/chemistry
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomes/genetics
- Ribosomes/metabolism
- Ribosomes/ultrastructure
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Affiliation(s)
- Satabdi Mishra
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Tofayel Ahmed
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anu Tyagi
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jian Shi
- Center for BioImaging Sciences, National University of Singapore, Singapore, Singapore
| | - Shashi Bhushan
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
- NTU Institute of Structural Biology, Nanyang Technological University, Singapore, Singapore.
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Abstract
Mycobacteria as well as other bacteria remodel their ribosomes in response to zinc depletion by replacing zinc-binding ribosomal proteins with zinc-free paralogues, releasing zinc for other metabolic processes. In this study, we show that the remodeled ribosome acquires a structurally stable but functionally inactive and aminoglycoside-resistant state in zinc-starved Mycobacterium smegmatis. Conversely, M. smegmatis cells that are growth arrested in zinc-rich conditions have unstable ribosomes and reduced survival. We further provide evidence for ribosome remodeling in Mycobacterium tuberculosis in host tissues, suggesting that ribosome hibernation occurs during TB infections. Our findings could offer insights into mechanisms of persistence and antibiotic tolerance of mycobacterial infections. Bacteria respond to zinc starvation by replacing ribosomal proteins that have the zinc-binding CXXC motif (C+) with their zinc-free (C−) paralogues. Consequences of this process beyond zinc homeostasis are unknown. Here, we show that the C− ribosome in Mycobacterium smegmatis is the exclusive target of a bacterial protein Y homolog, referred to as mycobacterial-specific protein Y (MPY), which binds to the decoding region of the 30S subunit, thereby inactivating the ribosome. MPY binding is dependent on another mycobacterial protein, MPY recruitment factor (MRF), which is induced on zinc depletion, and interacts with C− ribosomes. MPY binding confers structural stability to C− ribosomes, promoting survival of growth-arrested cells under zinc-limiting conditions. Binding of MPY also has direct influence on the dynamics of aminoglycoside-binding pockets of the C− ribosome to inhibit binding of these antibiotics. Together, our data suggest that zinc limitation leads to ribosome hibernation and aminoglycoside resistance in mycobacteria. Furthermore, our observation of the expression of the proteins of C− ribosomes in Mycobacterium tuberculosis in a mouse model of infection suggests that ribosome hibernation could be relevant in our understanding of persistence and drug tolerance of the pathogen encountered during chemotherapy of TB.
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