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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Grimberg H, Tiwari VS, Tam B, Gur-Arie L, Gingold D, Polachek L, Akabayov B. Machine learning approaches to optimize small-molecule inhibitors for RNA targeting. J Cheminform 2022; 14:4. [PMID: 35109921 PMCID: PMC8811966 DOI: 10.1186/s13321-022-00583-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 01/17/2022] [Indexed: 01/22/2023] Open
Abstract
In the era of data science, data-driven algorithms have emerged as powerful platforms that can consolidate bioisosteric rules for preferential modifications on small molecules with a common molecular scaffold. Here we present complementary data-driven algorithms to minimize the search in chemical space for phenylthiazole-containing molecules that bind the RNA hairpin within the ribosomal peptidyl transferase center (PTC) of Mycobacterium tuberculosis. Our results indicate visual, geometrical, and chemical features that enhance the binding to the targeted RNA. Functional validation was conducted after synthesizing 10 small molecules pinpointed computationally. Four of the 10 were found to be potent inhibitors that target hairpin 91 in the ribosomal PTC of M. tuberculosis and, as a result, stop translation.
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Affiliation(s)
- Hadar Grimberg
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Vinay S Tiwari
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Benjamin Tam
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Lihi Gur-Arie
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Daniela Gingold
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Lea Polachek
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Barak Akabayov
- Department of Chemistry and Data Science Research Center, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel.
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Gao X, Yu X, Zhu K, Qin B, Wang W, Han P, Aleksandra Wojdyla J, Wang M, Cui S. Crystal Structure of Mycobacterium tuberculosis Elongation Factor G1. Front Mol Biosci 2021; 8:667638. [PMID: 34540889 PMCID: PMC8446442 DOI: 10.3389/fmolb.2021.667638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 08/19/2021] [Indexed: 11/24/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) caused an estimated 10 million cases of tuberculosis and 1.2 million deaths in 2019 globally. The increasing emergence of multidrug-resistant and extensively drug-resistant Mtb is becoming a public health threat worldwide and makes the identification of anti-Mtb drug targets urgent. Elongation factor G (EF-G) is involved in tRNA translocation on ribosomes during protein translation. Therefore, EF-G is a major focus of structural analysis and a valuable drug target of antibiotics. However, the crystal structure of Mtb EF-G1 is not yet available, and this has limited the design of inhibitors. Here, we report the crystal structure of Mtb EF-G1 in complex with GDP. The unique crystal form of the Mtb EF-G1-GDP complex provides an excellent platform for fragment-based screening using a crystallographic approach. Our findings provide a structure-based explanation for GDP recognition, and facilitate the identification of EF-G1 inhibitors with potential interest in the context of drug discovery.
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Affiliation(s)
- Xiaopan Gao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xia Yu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,National Clinical Laboratory on Tuberculosis, Beijing Key Laboratory for Drug-resistant Tuberculosis Research Beijing Chest Hospital, Beijing Tuberculosis and Thoracic Tumor Institute, Capital Medical University, Beijing, China
| | - Kaixiang Zhu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bo Qin
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wei Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Pu Han
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | | | - Meitian Wang
- Swiss Light Source at the Paul Scherrer Institut, Villigen, Switzerland
| | - Sheng Cui
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, And Center for Tuberculosis Research, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.,Sanming Project of Medicine in Shenzhen on Construction of Novel Systematic Network Against Tuberculosis, National Clinical Research Center for Infectious Diseases, Shenzhen Third People's Hospital, Southern University of Science and Technology, Shenzhen, China
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4
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Aseev LV, Koledinskaya LS, Bychenko OS, Boni IV. Regulation of Ribosomal Protein Synthesis in Mycobacteria: The Autogenous Control of rpsO. Int J Mol Sci 2021; 22:9679. [PMID: 34575857 PMCID: PMC8470358 DOI: 10.3390/ijms22189679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/02/2021] [Accepted: 09/03/2021] [Indexed: 01/23/2023] Open
Abstract
The autogenous regulation of ribosomal protein (r-protein) synthesis plays a key role in maintaining the stoichiometry of ribosomal components in bacteria. In this work, taking the rpsO gene as a classic example, we addressed for the first time the in vivo regulation of r-protein synthesis in the mycobacteria M. smegmatis (Msm) and M. tuberculosis (Mtb). We used a strategy based on chromosomally integrated reporters under the control of the rpsO regulatory regions and the ectopic expression of Msm S15 to measure its impact on the reporter expression. Because the use of E. coli as a host appeared inefficient, a fluorescent reporter system was developed by inserting Msm or Mtb rpsO-egfp fusions into the Msm chromosome and expressing Msm S15 or E. coli S15 in trans from a novel replicative shuttle vector, pAMYC. The results of the eGFP expression measurements in Msm cells provided evidence that the rpsO gene in Msm and Mtb was feedback-regulated at the translation level. The mutagenic analysis showed that the folding of Msm rpsO 5'UTR in a pseudoknot appeared crucial for repression by both Msm S15 and E. coli S15, thus indicating a striking resemblance of the rpsO feedback control in mycobacteria and in E. coli.
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Affiliation(s)
| | | | | | - Irina V. Boni
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia; (L.V.A.); (L.S.K.); (O.S.B.)
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Nagai R, Xu Y, Liu C, Shimabukuro A, Takeuchi-Tomita N. In Vitro Reconstitution of Yeast Translation System Capable of Synthesizing Long Polypeptide and Recapitulating Programmed Ribosome Stalling. Methods Protoc 2021; 4:45. [PMID: 34287320 DOI: 10.3390/mps4030045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/19/2021] [Accepted: 06/24/2021] [Indexed: 12/27/2022] Open
Abstract
The rates of translation elongation or termination in eukaryotes are modulated through cooperative molecular interactions involving mRNA, the ribosome, aminoacyl- and nascent polypeptidyl-tRNAs, and translation factors. To investigate the molecular mechanisms underlying these processes, we developed an in vitro translation system from yeast, reconstituted with purified translation elongation and termination factors, utilizing CrPV IGR IRES-containing mRNA, which functions in the absence of initiation factors. The system is capable of synthesizing not only short oligopeptides but also long reporter proteins such as nanoluciferase. By setting appropriate translation reaction conditions, such as the Mg2+/polyamine concentration, the arrest of translation elongation by known ribosome-stalling sequences (e.g., polyproline and CGA codon repeats) is properly recapitulated in this system. We describe protocols for the preparation of the system components, manipulation of the system, and detection of the translation products. We also mention critical parameters for setting up the translation reaction conditions. This reconstituted translation system not only facilitates biochemical analyses of translation but is also useful for various applications, such as structural and functional studies with the aim of designing drugs that act on eukaryotic ribosomes, and the development of systems for producing novel functional proteins by incorporating unnatural amino acids by eukaryotic ribosomes.
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Abe T, Nagai R, Imataka H, Takeuchi-Tomita N. Reconstitution of yeast translation elongation and termination in vitro utilizing CrPV IRES-containing mRNA. J Biochem 2021; 167:441-450. [PMID: 32053165 DOI: 10.1093/jb/mvaa021] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 01/24/2020] [Indexed: 11/13/2022] Open
Abstract
We developed an in vitro translation system from yeast, reconstituted with purified translation elongation and termination factors and programmed by CrPV IGR IRES-containing mRNA, which functions in the absence of initiation factors. The system is capable of synthesizing the active reporter protein, nanoLuciferase, with a molecular weight of 19 kDa. The protein synthesis by the system is appropriately regulated by controlling its composition, including translation factors, amino acids and antibiotics. We found that a high eEF1A concentration relative to the ribosome concentration is critically required for efficient IRES-mediated translation initiation, to ensure its dominance over IRES-independent random internal translation initiation.
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Affiliation(s)
- Taisho Abe
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Riku Nagai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Hiroaki Imataka
- Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, Himeji 671-2201, Japan
| | - Nono Takeuchi-Tomita
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5, Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
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Harnagel A, Lopez Quezada L, Park SW, Baranowski C, Kieser K, Jiang X, Roberts J, Vaubourgeix J, Yang A, Nelson B, Fay A, Rubin E, Ehrt S, Nathan C, Lupoli TJ. Nonredundant functions of Mycobacterium tuberculosis chaperones promote survival under stress. Mol Microbiol 2020; 115:272-289. [PMID: 32996193 DOI: 10.1111/mmi.14615] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
Bacterial chaperones ClpB and DnaK, homologs of the respective eukaryotic heat shock proteins Hsp104 and Hsp70, are essential in the reactivation of toxic protein aggregates that occur during translation or periods of stress. In the pathogen Mycobacterium tuberculosis (Mtb), the protective effect of chaperones extends to survival in the presence of host stresses, such as protein-damaging oxidants. However, we lack a full understanding of the interplay of Hsps and other stress response genes in mycobacteria. Here, we employ genome-wide transposon mutagenesis to identify the genes that support clpB function in Mtb. In addition to validating the role of ClpB in Mtb's response to oxidants, we show that HtpG, a homolog of Hsp90, plays a distinct role from ClpB in the proteotoxic stress response. While loss of neither clpB nor htpG is lethal to the cell, loss of both through genetic depletion or small molecule inhibition impairs recovery after exposure to host-like stresses, especially reactive nitrogen species. Moreover, defects in cells lacking clpB can be complemented by overexpression of other chaperones, demonstrating that Mtb's stress response network depends upon finely tuned chaperone expression levels. These results suggest that inhibition of multiple chaperones could work in concert with host immunity to disable Mtb.
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Affiliation(s)
- Alexa Harnagel
- Department of Chemistry, New York University, New York, NY, USA
| | - Landys Lopez Quezada
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Sae Woong Park
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Catherine Baranowski
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Karen Kieser
- Department of Immunology and Infectious Disease, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Xiuju Jiang
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Julia Roberts
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Julien Vaubourgeix
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Amy Yang
- Department of Chemistry, New York University, New York, NY, USA
| | - Brock Nelson
- Department of Chemistry, New York University, New York, NY, USA
| | - Allison Fay
- Immunology Program, Sloan Kettering Institute, New York, NY, USA
| | - Eric Rubin
- Immunology Program, Sloan Kettering Institute, New York, NY, USA
| | - Sabine Ehrt
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Carl Nathan
- Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
| | - Tania J Lupoli
- Department of Chemistry, New York University, New York, NY, USA.,Department of Microbiology and Immunology, Weill Cornell Medicine, New York, NY, USA
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Vargas-Blanco DA, Zhou Y, Zamalloa LG, Antonelli T, Shell SS. mRNA Degradation Rates Are Coupled to Metabolic Status in Mycobacterium smegmatis. mBio 2019; 10:e00957-19. [PMID: 31266866 DOI: 10.1128/mBio.00957-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The logistics of tuberculosis therapy are difficult, requiring multiple drugs for many months. Mycobacterium tuberculosis survives in part by entering nongrowing states in which it is metabolically less active and thus less susceptible to antibiotics. Basic knowledge on how M. tuberculosis survives during these low-metabolism states is incomplete, and we hypothesize that optimized energy resource management is important. Here, we report that slowed mRNA turnover is a common feature of mycobacteria under energy stress but is not dependent on the mechanisms that have generally been postulated in the literature. Finally, we found that mRNA stability and growth status can be decoupled by a drug that causes growth arrest but increases metabolic activity, indicating that mRNA stability responds to metabolic status rather than to growth rate per se. Our findings suggest a need to reorient studies of global mRNA stabilization to identify novel mechanisms that are presumably responsible. The success of Mycobacterium tuberculosis as a human pathogen is due in part to its ability to survive stress conditions, such as hypoxia or nutrient deprivation, by entering nongrowing states. In these low-metabolism states, M. tuberculosis can tolerate antibiotics and develop genetically encoded antibiotic resistance, making its metabolic adaptation to stress crucial for survival. Numerous bacteria, including M. tuberculosis, have been shown to reduce their rates of mRNA degradation under growth limitation and stress. While the existence of this response appears to be conserved across species, the underlying bacterial mRNA stabilization mechanisms remain unknown. To better understand the biology of nongrowing mycobacteria, we sought to identify the mechanistic basis of mRNA stabilization in the nonpathogenic model Mycobacterium smegmatis. We found that mRNA half-life was responsive to energy stress, with carbon starvation and hypoxia causing global mRNA stabilization. This global stabilization was rapidly reversed when hypoxia-adapted cultures were reexposed to oxygen, even in the absence of new transcription. The stringent response and RNase levels did not explain mRNA stabilization, nor did transcript abundance. This led us to hypothesize that metabolic changes during growth cessation impact the activities of degradation proteins, increasing mRNA stability. Indeed, bedaquiline and isoniazid, two drugs with opposing effects on cellular energy status, had opposite effects on mRNA half-lives in growth-arrested cells. Taken together, our results indicate that mRNA stability in mycobacteria is not directly regulated by growth status but rather is dependent on the status of energy metabolism.
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Govindan A, Miryala S, Mondal S, Varshney U. Development of Assay Systems for Amber Codon Decoding at the Steps of Initiation and Elongation in Mycobacteria. J Bacteriol 2018; 200:e00372-18. [PMID: 30181124 DOI: 10.1128/JB.00372-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/24/2018] [Indexed: 11/20/2022] Open
Abstract
Genetic analysis of the mechanism of protein synthesis in Gram-positive bacteria has remained largely unexplored because of the unavailability of appropriate in vivo assay systems. We developed chloramphenicol acetyltransferase (CAT)-based in vivo reporter systems to study translation initiation and elongation in Mycobacterium smegmatis The CAT reporters utilize specific decoding of amber codons by mutant initiator tRNA (i-tRNA, metU) molecules containing a CUA anticodon (metU CUA). The assay systems allow structure-function analyses of tRNAs without interfering with the cellular protein synthesis and function with or without the expression of heterologous GlnRS from Escherichia coli We show that despite their naturally occurring slow-growth phenotypes, the step of i-tRNA formylation is vital in translation initiation in mycobacteria and that formylation-deficient i-tRNA mutants (metU CUA/A1, metU CUA/G72, and metU CUA/G72G73) with a Watson-Crick base pair at the 1·72 position participate in elongation. In the absence of heterologous GlnRS expression, the mutant tRNAs are predominantly aminoacylated (glutamylated) by nondiscriminating GluRS. Acid urea gels show complete transamidation of the glutamylated metU CUA/G72G73 tRNA to its glutaminylated form (by GatCAB) in M. smegmatis In contrast, the glutamylated metU CUA/G72 tRNA did not show a detectable level of transamidation. Interestingly, the metU CUA/A1 mutant showed an intermediate activity of transamidation and accumulated in both glutamylated and glutaminylated forms. These observations suggest important roles for the discriminator base position and/or a weak Watson-Crick base pair at 1·72 for in vivo recognition of the glutamylated tRNAs by M. smegmatis GatCAB.IMPORTANCE Genetic analysis of the translational apparatus in Gram-positive bacteria has remained largely unexplored because of the unavailability of appropriate in vivo assay systems. We developed chloramphenicol acetyltransferase (CAT)-based reporters which utilize specific decoding of amber codons by mutant tRNAs at the steps of initiation and/or elongation to allow structure-function analysis of the translational machinery. We show that formylation of the initiator tRNA (i-tRNA) is crucial even for slow-growing bacteria and that i-tRNA mutants with a CUA anticodon are aminoacylated by nondiscriminating GluRS. The discriminator base position, and/or a weak Watson-Crick base pair at the top of the acceptor stem, provides important determinants for transamidation of the i-tRNA-attached Glu to Gln by the mycobacterial GatCAB.
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Yamada H, Yamaguchi M, Igarashi Y, Chikamatsu K, Aono A, Murase Y, Morishige Y, Takaki A, Chibana H, Mitarai S. Mycolicibacterium smegmatis, Basonym Mycobacterium smegmatis, Expresses Morphological Phenotypes Much More Similar to Escherichia coli Than Mycobacterium tuberculosis in Quantitative Structome Analysis and CryoTEM Examination. Front Microbiol 2018; 9:1992. [PMID: 30258411 PMCID: PMC6145149 DOI: 10.3389/fmicb.2018.01992] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/07/2018] [Indexed: 01/05/2023] Open
Abstract
A series of structome analyses, that is, quantitative and three-dimensional structural analysis of a whole cell at the electron microscopic level, have already been achieved individually in Exophiala dermatitidis, Saccharomyces cerevisiae, Mycobacterium tuberculosis, Myojin spiral bacteria, and Escherichia coli. In these analyses, sample cells were processed through cryo-fixation and rapid freeze-substitution, resulting in the exquisite preservation of ultrastructures on the serial ultrathin sections examined by transmission electron microscopy. In this paper, structome analysis of non pathogenic Mycolicibacterium smegmatis, basonym Mycobacterium smegmatis, was performed. As M. smegmatis has often been used in molecular biological experiments and experimental tuberculosis as a substitute of highly pathogenic M. tuberculosis, it has been a task to compare two species in the same genus, Mycobacterium, by structome analysis. Seven M. smegmatis cells cut into serial ultrathin sections, and, totally, 220 serial ultrathin sections were examined by transmission electron microscopy. Cell profiles were measured, including cell length, diameter of cell and cytoplasm, surface area of outer membrane and plasma membrane, volume of whole cell, periplasm, and cytoplasm, and total ribosome number and density per 0.1 fl cytoplasm. These data are based on direct measurement and enumeration of exquisitely preserved single cell structures in the transmission electron microscopy images, and are not based on the calculation or assumptions from biochemical or molecular biological indirect data. All measurements in M. smegmatis, except cell length, are significantly higher than those of M. tuberculosis. In addition, these data may explain the more rapid growth of M. smegmatis than M. tuberculosis and contribute to the understanding of their structural properties, which are substantially different from M. tuberculosis, relating to the expression of antigenicity, acid-fastness, and the mechanism of drug resistance in relation to the ratio of the targets to the corresponding drugs. In addition, data obtained from cryo-transmission electron microscopy examination were used to support the validity of structome analysis. Finally, our data strongly support the most recent establishment of the novel genus Mycolicibacterium, into which basonym Mycobacterium smegmatis has been classified.
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Affiliation(s)
- Hiroyuki Yamada
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | | | - Yuriko Igarashi
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Kinuyo Chikamatsu
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Akio Aono
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Yoshiro Murase
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Yuta Morishige
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Akiko Takaki
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
| | - Hiroji Chibana
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Satoshi Mitarai
- Department of Mycobacterium Reference and Research, The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Kiyose, Japan
- Department of Basic Mycobacteriology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
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Li X, Jiang Y, Chong S, Walt DR. Bottom-up single-molecule strategy for understanding subunit function of tetrameric β-galactosidase. Proc Natl Acad Sci U S A 2018; 115:8346-51. [PMID: 30061400 DOI: 10.1073/pnas.1805690115] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this paper, we report an example of the engineered expression of tetrameric β-galactosidase (β-gal) containing varying numbers of active monomers. Specifically, by combining wild-type and single-nucleotide polymorphism plasmids at varying ratios, tetrameric β-gal was expressed in vitro with one to four active monomers. The kinetics of individual enzyme molecules revealed four distinct populations, corresponding to the number of active monomers in the enzyme. Using single-molecule-level enzyme kinetics, we were able to measure an accurate in vitro mistranslation frequency (5.8 × 10-4 per base). In addition, we studied the kinetics of the mistranslated β-gal at the single-molecule level.
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Wang W, Qin B, Wojdyla JA, Wang M, Gao X, Cui S. Structural characterization of free-state and product-state Mycobacterium tuberculosis methionyl-tRNA synthetase reveals an induced-fit ligand-recognition mechanism. IUCrJ 2018; 5:478-490. [PMID: 30002848 PMCID: PMC6038951 DOI: 10.1107/s2052252518008217] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 06/04/2018] [Indexed: 06/08/2023]
Abstract
Mycobacterium tuberculosis (MTB) caused 10.4 million cases of tuberculosis and 1.7 million deaths in 2016. The incidence of multidrug-resistant and extensively drug-resistant MTB is becoming an increasing threat to public health and the development of novel anti-MTB drugs is urgently needed. Methionyl-tRNA synthetase (MetRS) is considered to be a valuable drug target. However, structural characterization of M. tuberculosis MetRS (MtMetRS) was lacking for decades, thus hampering drug design. Here, two high-resolution crystal structures of MtMetRS are reported: the free-state structure (apo form; 1.9 Å resolution) and a structure with the intermediate product methionyl-adenylate (Met-AMP) bound (2.4 Å resolution). It was found that free-state MtMetRS adopts a previously unseen conformation that has never been observed in other MetRS homologues. The pockets for methionine and AMP are not formed in free-state MtMetRS, suggesting that it is in a nonproductive conformation. Combining these findings suggests that MtMetRS employs an induced-fit mechanism in ligand binding. By comparison with the structure of human cytosolic MetRS, additional pockets specific to MtMetRS that could be used for anti-MTB drug design were located.
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Affiliation(s)
- Wei Wang
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | - Bo Qin
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | | | - Meitian Wang
- Paul Scherrer Institute, Swiss Light Source, CH-5232 Villigen, Switzerland
| | - Xiaopan Gao
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
| | - Sheng Cui
- MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Science, No. 9 Dong Dan San Tiao, Dong Cheng Qu, Beijing 100730, People’s Republic of China
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Fujiwara K, Sawamura T, Niwa T, Deyama T, Nomura SIM, Taguchi H, Doi N. In vitro transcription-translation using bacterial genome as a template to reconstitute intracellular profile. Nucleic Acids Res 2017; 45:11449-11458. [PMID: 28977538 PMCID: PMC5737407 DOI: 10.1093/nar/gkx776] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/24/2017] [Indexed: 12/13/2022] Open
Abstract
In vitro transcription–translation systems (TX–TL) can synthesize most of individual genes encoded in genomes by using strong promoters and translation initiation sequences. This fact raises a possibility that TX–TL using genome as a template can reconstitute the profile of RNA and proteins in living cells. By using cell extracts and genome prepared from different organisms, here we developed a system for in vitro genome transcription–translation (iGeTT) using bacterial genome and cell extracts, and surveyed de novo synthesis of RNA and proteins. Two-dimensional electrophoresis and nano LC–MS/MS showed that proteins were actually expressed by iGeTT. Quantitation of transcription levels of 50 genes for intracellular homeostasis revealed that the levels of RNA synthesis by iGeTT are highly correlated with those in growth phase cells. Furthermore, activity of iGeTT was influenced by transcription derived from genome structure and gene location in genome. These results suggest that intracellular profiles and characters of genome can be emulated by TX–TL using genome as a template.
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Affiliation(s)
- Kei Fujiwara
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan
- To whom correspondence should be addressed. Tel: +81 45 566 1533;
| | - Tsunehito Sawamura
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Tatsuya Niwa
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Tatsuki Deyama
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan
| | - Shin-ichiro M. Nomura
- Department of Robotics, School of Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Hideki Taguchi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Nobuhide Doi
- Department of Biosciences and Informatics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan
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