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Protein Synthesis

Protein Synthesis. Ribosomes. 16S rRNA Secondary Structures. 30S Subunit Structure: 16S rRNA & proteins. Electron Density Models of Both Subunits & tRNAs. 70S Ribosome Showing tRNAs in A, P & E Sites. Prokaryotic Ribosomes. tRNA Structure. tRNA Structure. Modified Bases.

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Protein Synthesis

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  1. Protein Synthesis

  2. Ribosomes

  3. 16S rRNA Secondary Structures

  4. 30S Subunit Structure: 16S rRNA & proteins

  5. Electron Density Models of Both Subunits & tRNAs

  6. 70S Ribosome Showing tRNAs in A, P & E Sites

  7. Prokaryotic Ribosomes

  8. tRNA Structure

  9. tRNA Structure

  10. Modified Bases

  11. Codon - Anticodon Base-Pairing - Role of Wobble Bases

  12. The Genetic Code

  13. Aminoacyl Transferase Determines Specificity of Amino Acid Inserted at a Codon

  14. Aminoacyl-tRNA Synthetase Function

  15. Aminoacyl tRNA Synthetase Structure

  16. Chemistry of Aminoacylation

  17. eIF-1 Promotes dissociation of 80S ribosomes Binds after eIF-4 and allows scanning to begin eIF-2 GTPase activated by 60S subunit binding Stabilizes binding of initiator met-tRNAimet eIF-3 Promotes 80S ribosome dissociation Binds to 40S subunit & prevents reassociation of 60S subunit Promotes binding of eIF-2 eIF-4 Multi-component complex Recruits mRNA binding Recognizes cap, pA tail Promotes binding of eIF-1 for scanning eIF-5 Promotes reformation of 80S ribosome Displaces eIF-6 eIF-6 Promotes dissociation of 80S ribosome Binds 60S subunit & prevents reassociation with 40S subunit Roles of Eukaryotic Initiation Factors

  18. Translation Initiation

  19. Steps in Eukaryotic Translation Initiation eIF-1 + eIF-6 eIF-1 + eIF3 eIF-6

  20. eIF4 Complex Components & Functions • eIF4E – Cap binding • eIF4G – eIF3 binding PAB1P binding eIF4A – helicase eIF4B – stimulates RNA binding of eIF4A

  21. Scanning Model of Eukaryotic Translation Initiation Requirements: Must be able to determine which AUG is the right one to start translation

  22. Kozack Consensus CCRCCAUGG

  23. Overview of Elongation

  24. Elongation Step 1: Binding of aa-tRNA Eukaryotic counterparts: EF1 EF1

  25. Kinetics of First Elongation Step Allow Proofreading Rib = ribosome + met-tRNAimet TC=EF1·GTP ·aa-tRNA

  26. Peptidyl Transferase is Large Ribosomal Subunit

  27. Peptidyl Transferase Active Site & Reaction Mechanism

  28. GTP Hydrolysis Is Required for Translocation Eukaryotic counterpart: EF-2

  29. Structure of EF-G Compared to EF-Tu•tRNA Complex EF-Tu•tRNA EF-G

  30. Overview of Elongation

  31. Elongation

  32. Translocation

  33. Similarity Between eRF1 Tertiary Structure and tRNA

  34. Termination Factors RF-3 & eRF-2 RF-3 – Prokaryotic eRF-2 – Eukaryotic Are GTPases that catalyzes the actual cleavage of the pep-tRNA bond to release the peptide

  35. Protein Folding

  36. Protein Folding

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