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Full-Text Articles in Medicine and Health Sciences
Starvation Sensing By Mycobacterial Rela/Spot Homologue Through Constitutive Surveillance Of Translation, Yunlong Li, Soneya Majumdar, Ryan Treen, Manjuli R. Sharma, Jamie Corro, Howard B. Gamper, Swati R. Manjari, Jerome Prusa, Nilesh K. Banavali, Christina L. Stallings, Ya-Ming Hou, Rajendra K. Agrawal, Anil K. Ojha
Starvation Sensing By Mycobacterial Rela/Spot Homologue Through Constitutive Surveillance Of Translation, Yunlong Li, Soneya Majumdar, Ryan Treen, Manjuli R. Sharma, Jamie Corro, Howard B. Gamper, Swati R. Manjari, Jerome Prusa, Nilesh K. Banavali, Christina L. Stallings, Ya-Ming Hou, Rajendra K. Agrawal, Anil K. Ojha
Department of Biochemistry and Molecular Biology Faculty Papers
The stringent response, which leads to persistence of nutrient-starved mycobacteria, is induced by activation of the RelA/SpoT homolog (Rsh) upon entry of a deacylated-tRNA in a translating ribosome. However, the mechanism by which Rsh identifies such ribosomes in vivo remains unclear. Here, we show that conditions inducing ribosome hibernation result in loss of intracellular Rsh in a Clp protease-dependent manner. This loss is also observed in nonstarved cells using mutations in Rsh that block its interaction with the ribosome, indicating that Rsh association with the ribosome is important for Rsh stability. The cryo-EM structure of the Rsh-bound 70S ribosome in …
Role Of Ribosome Recycling Factor In Natural Termination And Translational Coupling As A Ribosome Releasing Factor, Yoshio Inokuchi, Fabio Quaglia, Akikazu Hirashima, Yoshihiro Yamamoto, Hideko Kaji, Akira Kaji
Role Of Ribosome Recycling Factor In Natural Termination And Translational Coupling As A Ribosome Releasing Factor, Yoshio Inokuchi, Fabio Quaglia, Akikazu Hirashima, Yoshihiro Yamamoto, Hideko Kaji, Akira Kaji
Department of Biochemistry and Molecular Biology Faculty Papers
The role of ribosome recycling factor (RRF) of E. coli was studied in vivo and in vitro. We used the translational coupling without the Shine-Dalgarno sequence of downstream ORF (d-ORF) as a model system of the RRF action in natural termination of protein synthesis. For the in vivo studies we used the translational coupling by the adjacent coat and lysis genes of RNA phage GA sharing the termination and initiation (UAAUG) and temperature sensitive RRF. The d-ORF translation was measured by the expression of the reporter lacZ gene connected to the 5'-terminal part of the lysis gene. The results showed …
Interplay Between An Atp-Binding Cassette F Protein And The Ribosome From Mycobacterium Tuberculosis, Zhicheng Cui, Xiaojun Li, Joonyoung Shin, Howard Gamper, Ya-Ming Hou, James C Sacchettini, Junjie Zhang
Interplay Between An Atp-Binding Cassette F Protein And The Ribosome From Mycobacterium Tuberculosis, Zhicheng Cui, Xiaojun Li, Joonyoung Shin, Howard Gamper, Ya-Ming Hou, James C Sacchettini, Junjie Zhang
Department of Biochemistry and Molecular Biology Faculty Papers
EttA, energy-dependent translational throttle A, is a ribosomal factor that gates ribosome entry into the translation elongation cycle. A detailed understanding of its mechanism of action is limited due to the lack of high-resolution structures along its ATPase cycle. Here we present the cryo-electron microscopy (cryo-EM) structures of EttA from Mycobacterium tuberculosis (Mtb), referred to as MtbEttA, in complex with the Mtb 70S ribosome initiation complex (70SIC) at the pre-hydrolysis (ADPNP) and transition (ADP-VO4) states, and the crystal structure of MtbEttA alone in the post-hydrolysis (ADP) state. We observe that MtbEttA binds the E-site of the Mtb 70SIC, remodeling the …
Time-Resolved Cryo-Em Visualizes Ribosomal Translocation With Ef-G And Gtp, Christine E Carbone, Anna B Loveland, Howard Gamper, Ya-Ming Hou, Gabriel Demo, Andrei A Korostelev
Time-Resolved Cryo-Em Visualizes Ribosomal Translocation With Ef-G And Gtp, Christine E Carbone, Anna B Loveland, Howard Gamper, Ya-Ming Hou, Gabriel Demo, Andrei A Korostelev
Department of Biochemistry and Molecular Biology Faculty Papers
During translation, a conserved GTPase elongation factor-EF-G in bacteria or eEF2 in eukaryotes-translocates tRNA and mRNA through the ribosome. EF-G has been proposed to act as a flexible motor that propels tRNA and mRNA movement, as a rigid pawl that biases unidirectional translocation resulting from ribosome rearrangements, or by various combinations of motor- and pawl-like mechanisms. Using time-resolved cryo-EM, we visualized GTP-catalyzed translocation without inhibitors, capturing elusive structures of ribosome•EF-G intermediates at near-atomic resolution. Prior to translocation, EF-G binds near peptidyl-tRNA, while the rotated 30S subunit stabilizes the EF-G GTPase center. Reverse 30S rotation releases Pi and translocates peptidyl-tRNA and …
Protein Synthesis Factors (Rf1, Rf2, Rf3, Rrf, And Tmrna) And Peptidyl-Trna Hydrolase Rescue Stalled Ribosomes At Sense Codons., Serafín Vivanco-Domínguez, José Bueno-Martínez, Gloria León-Avila, Nobuhiro Iwakura, Akira Kaji, Hideko Kaji, Gabriel Guarneros
Protein Synthesis Factors (Rf1, Rf2, Rf3, Rrf, And Tmrna) And Peptidyl-Trna Hydrolase Rescue Stalled Ribosomes At Sense Codons., Serafín Vivanco-Domínguez, José Bueno-Martínez, Gloria León-Avila, Nobuhiro Iwakura, Akira Kaji, Hideko Kaji, Gabriel Guarneros
Department of Biochemistry and Molecular Biology Faculty Papers
During translation, ribosomes stall on mRNA when the aminoacyl-tRNA to be read is not readily available. The stalled ribosomes are deleterious to the cell and should be rescued to maintain its viability. To investigate the contribution of some of the cellular translation factors on ribosome rescuing, we provoked stalling at AGA codons in mutants that affected the factors and then analyzed the accumulation of oligopeptidyl (peptides of up to 6 amino acid residues, oligopep-)-tRNA or polypeptidyl (peptides of more than 300 amino acids in length, polypep-)-tRNA associated with ribosomes. Stalling was achieved by starvation for aminoacyl-tRNA(Arg4) upon induced expression of …
Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji
Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji
Department of Biochemistry and Molecular Biology Faculty Papers
After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a new round of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5gamma'-(beta,gamma-imido)triphosphate did not function at all. The k(cat) of eEF3 was 1.12 min(-1), which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated …
The Role Of Gtp In Transient Splitting Of 70s Ribosomes By Rrf (Ribosome Recycling Factor) And Ef-G (Elongation Factor G)., Go Hirokawa, Nobuhiro Iwakura, Akira Kaji, Hideko Kaji
The Role Of Gtp In Transient Splitting Of 70s Ribosomes By Rrf (Ribosome Recycling Factor) And Ef-G (Elongation Factor G)., Go Hirokawa, Nobuhiro Iwakura, Akira Kaji, Hideko Kaji
Department of Biochemistry and Molecular Biology Faculty Papers
Ribosome recycling factor (RRF), elongation factor G (EF-G) and GTP split 70S ribosomes into subunits. Here, we demonstrated that the splitting was transient and the exhaustion of GTP resulted in re-association of the split subunits into 70S ribosomes unless IF3 (initiation factor 3) was present. However, the splitting was observed with sucrose density gradient centrifugation (SDGC) without IF3 if RRF, EF-G and GTP were present in the SDGC buffer. The splitting of 70S ribosomes causes the decrease of light scattering by ribosomes. Kinetic constants obtained from the light scattering studies are sufficient to account for the splitting of 70S ribosomes …