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GTPase Mechanisms and Functions of Translation Factors on the Ribosome

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Published/Copyright: July 5, 2005
Biological Chemistry
From the journal Volume 381 Issue 5-6

Abstract

The elongation factors (EF) Tu and G and initiation factor 2 (IF2) from bacteria are multidomain GTPases with essential functions in the elongation and initiation phases of translation. They bind to the same site on the ribosome where their low intrinsic GTPase activities are strongly stimulated. The factors differ fundamentally from each other, and from the majority of GTPases, in the mechanisms of GTPase control, the timing of Pi release, and the functional role of GTP hydrolysis. EF-Tu·GTP forms a ternary complex with aminoacyl-tRNA, which binds to the ribosome. Only when a matching codon is recognized, the GTPase of EF-Tu is stimulated, rapid GTP hydrolysis and Pi release take place, EF-Tu rearranges to the GDP form, and aminoacyl-tRNA is released into the peptidyltransferase center. In contrast, EF-G hydrolyzes GTP immediately upon binding to the ribosome, stimulated by ribosomal protein L7/12. Subsequent translocation is driven by the slow dissociation of Pi, suggesting a mechano-chemical function of EF-G. Accordingly, different conformations of EF-G on the ribosome are revealed by cryo-electron microscopy. GTP hydrolysis by IF2 is triggered upon formation of the 70S initiation complex, and the dissociation of Pi and/or IF2 follows a rearrangement of the ribosome into the elongation-competent state.

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Published Online: 2005-07-05
Published in Print: 2000-06-21

Copyright © 2000 by Walter de Gruyter GmbH & Co. KG

Articles in the same Issue

  1. Highlight: GTP Binding Proteins Central Regulators in Cell Biology
  2. Signal Transduction and Post-Transcriptional Gene Expression
  3. Regulation of GTPases in the Bacterial Translation Machinery
  4. GTPase Mechanisms and Functions of Translation Factors on the Ribosome
  5. The Role of Heterotrimeric G Proteins in Platelet Activation
  6. Upstream and Downstream of Ran GTPase
  7. Nogo-A, a Potent Inhibitor of Neurite Outgrowth and Regeneration
  8. Rho GTPases as Targets of Bacterial Protein Toxins
  9. A Conserved Gβ Binding (GBB) Sequence Motif in Ste20p/PAK Family Protein Kinases
  10. Identification of a CpG Island in the Human LRP-2 Gene and Analysis of Its Methylation Status in Parathyroid Adenomas
  11. Theoretical Description of the Direct Exponential Amplification and Sequencing (DEXAS) Method
  12. Adenine Nucleotide N-Glycosidase Activity of the A-Chain of Cinnamomin Characterized by 1H-Nuclear Magnetic Resonance
  13. Msb4p, a Protein Involved in Cdc42p-Dependent Organization of the Actin Cytoskeleton, Is a Ypt/Rab-Specific GAP
  14. Muscle Phosphorylase Kinase Is Not a Substrate of AMP-Activated Protein Kinase
  15. Cationic Lipopolyamines Induce Degradation of PrPSc in Scrapie-Infected Mouse Neuroblastoma Cells
  16. Glycosylphosphatidylinositol-Specific Phospholipase D of Human Serum Activity Modulation by Naturally Occurring Amphiphiles
  17. Retrieval of the mrp2 Gene Encoded Conjugate Export Pump from the Canalicular Membrane Contributes to Cholestasis Induced by tert-Butyl Hydroperoxide and Chloro-Dinitrobenzene
  18. Matrix Metalloproteinases-2, -3, -7, -9 and -10, But Not MMP-11, Are Differentially Expressed in Normal, Benign Tumorigenic and Malignant Human Keratinocyte Cell Lines
  19. Human Keratinocyte Cell Lines Differ in the Expression of the Collagenolytic Matrix Metallo-proteinases-1, -8, and -13 and of TIMP-1
  20. Inducibility of the Streptomyces traRts107-Ptra Expression Cassette in Mycobacterium smegmatis
  21. Shortest Known Prion Protein Allele in Highly BSE-Susceptible Lemurs
  22. Prostaglandin Deficiency Promotes Sensitization of Adenylyl Cyclase
https://doi.org/10.1515/BC.2000.050

Articles in the same Issue

  1. Highlight: GTP Binding Proteins Central Regulators in Cell Biology
  2. Signal Transduction and Post-Transcriptional Gene Expression
  3. Regulation of GTPases in the Bacterial Translation Machinery
  4. GTPase Mechanisms and Functions of Translation Factors on the Ribosome
  5. The Role of Heterotrimeric G Proteins in Platelet Activation
  6. Upstream and Downstream of Ran GTPase
  7. Nogo-A, a Potent Inhibitor of Neurite Outgrowth and Regeneration
  8. Rho GTPases as Targets of Bacterial Protein Toxins
  9. A Conserved Gβ Binding (GBB) Sequence Motif in Ste20p/PAK Family Protein Kinases
  10. Identification of a CpG Island in the Human LRP-2 Gene and Analysis of Its Methylation Status in Parathyroid Adenomas
  11. Theoretical Description of the Direct Exponential Amplification and Sequencing (DEXAS) Method
  12. Adenine Nucleotide N-Glycosidase Activity of the A-Chain of Cinnamomin Characterized by 1H-Nuclear Magnetic Resonance
  13. Msb4p, a Protein Involved in Cdc42p-Dependent Organization of the Actin Cytoskeleton, Is a Ypt/Rab-Specific GAP
  14. Muscle Phosphorylase Kinase Is Not a Substrate of AMP-Activated Protein Kinase
  15. Cationic Lipopolyamines Induce Degradation of PrPSc in Scrapie-Infected Mouse Neuroblastoma Cells
  16. Glycosylphosphatidylinositol-Specific Phospholipase D of Human Serum Activity Modulation by Naturally Occurring Amphiphiles
  17. Retrieval of the mrp2 Gene Encoded Conjugate Export Pump from the Canalicular Membrane Contributes to Cholestasis Induced by tert-Butyl Hydroperoxide and Chloro-Dinitrobenzene
  18. Matrix Metalloproteinases-2, -3, -7, -9 and -10, But Not MMP-11, Are Differentially Expressed in Normal, Benign Tumorigenic and Malignant Human Keratinocyte Cell Lines
  19. Human Keratinocyte Cell Lines Differ in the Expression of the Collagenolytic Matrix Metallo-proteinases-1, -8, and -13 and of TIMP-1
  20. Inducibility of the Streptomyces traRts107-Ptra Expression Cassette in Mycobacterium smegmatis
  21. Shortest Known Prion Protein Allele in Highly BSE-Susceptible Lemurs
  22. Prostaglandin Deficiency Promotes Sensitization of Adenylyl Cyclase
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