Biochem 501: Part IV.10: Translation Biochem and Regulation

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Biochem 501: Part IV.10: Translation Biochem and Regulation
2013-12-06 20:19:06
Biochem 501 FINAL

Biochem 501 FINAL
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  1. Which amino acid initiates polypeptide synthesis:
    • Methionine: Cytosolic eukaryotic ribosomes
    • N-formylmethionine: prokaryotes, mitochondria/chloroplast ribosomes
  2. The Ribosome
    • Ribosome is complex structure
    • Ribosome functions:
    • -to facilitate translation
    • -catalyze peptide bond formation (largest subunit RNA is peptidyl transferase enzyme)
  3. Bacterial translation initiation complex
    • In bacteria, initiation involves base pair interactions between three different RNAs.
    • mRNA base pairs with RNA in small unit
    • This helps distinguish start AUG from other AUG
    • mRNA AUG base pairs with the fMET-tRNA anticodon loop.
    • Shine-Dalgarno sequences
  4. Initiating eukaryotic translation
    • AUG found via scanning (no Shine-Dalgarno)
    • 40S ribsome attaches that 5' and 3' mRNA ends
  5. Large Ribosomal subunit is:
    • The peptide Transferase
    • Peptidyl transferase active site is fully RNA
  6. Ribosomal Translation
  7. Mechanisms to Regulate polypeptide synthesis
    • Direct regulation by proteins: Protein can regulate translation by binding translation initiation signals. In eukaryotes this is usually proteins binding mRNA 3' end and interacting with 5' end
    • Antisense RNA:
    • Translation of some mRNAs is blocked by antisense RNAs that base pair with mRNA translation initiation signal sequences, preventing mRNA from interacting with rRNA and tRNA¬†
    • Transcription-translation coupling:
    • In prokaryotic cells, transcription /translation can be coupled. (Eukaryotes have transcription in nucleus and translation in cyto) Rate of translation can attenuate gene transcription to control polypeptide levels
  8. trp RNA forms ____ structures when ____ interact with each other
    distinct, different

    • (trp levels sifficient= transcription termination)
    • (trp levels low= transcription continues)
  9. Just look over this shit later
    Watch lecture or somethig