Prokaryyotic Translation

1. Translation In Prokaryote

2. Translation
 The process in which transcribed mRNA is used to
produce a specific amino acid chain, or polypeptide.

3. DNA
RNA(mRNA)
Proteins
Transcription
Replication
Translation

4. Steps in Translation
 Activating of Amino Acids
 Charging of tRNA (Amino Acylation of tRNA).
 Activation of Ribosome's
 Synthesis of polypeptide
- Initiation
- Elongation
- Termination
• Modification of polypeptide chain

5. Raw Material
 Amino Acids
 mRNA
 tRNA
 Ribosome
 Initiation factors, Termination factors.
 Enzymes(Aminoacyl tRNA synthase, Peptide
polymerase system)
 Inorganic cations such as Mg2+ ,k+ , NH+

6. Ribosome

7. mRNA

8. tRNA

9. Activation of Amino acids
Amino acids + ATP
Aminoacyl tRNA synthase
+
Mg2+
AA-AMP-complex
+
PPi

10. Charging of tRNA
AA-AMP-Enzyme + 3` tRNA
tRNA-AA-complex
Aminoacyl tRNA
synthase
• Aminoacyl tRNA complex is tRNA carrying Amino acid so called as
Adaptor tRNA

11. Synthesis of Polypeptide chain
 Three step process:-
- Initiation:-
-formation of initiation complex
- Elongation:-
- adding of amino acids to polypeptide chain
- Termination
- detachment of polypeptide chain from
translational complex

12. Initiation
• initiation factor:-
• IF1- stabilize smaller subunit of ribosome with mRNA.
• IF2- binds with initiator fMet-tRNAfMet.
• IF3- inhibit joining of larger subunit with smaller subunit.
30s subunit
30 s –IF1-IF3
IF1 + IF3

13. 30s- IF - IF3
30s-IF2-fMet tRNAfMet- mRNA
fMet-tRNA fMet
+
mRNA
+
IF2-GTP
This called Pre-Initiation complex

14. 30s-IF2-fMet tRNAfMet- mRNA
70 S -fMet tRNAfMet- mRNA
(70 S Initiation complex)

15. Elongation
• Addition of new
charged tRNA at A
• Peptide bonding between
fMet(Amino acid) and new
amino acid on tRNA

16. Translocation
• Shifting of A site tRNA
to P site.
• Shifting of P site tRNA
to E site.

17. • Repeating of cycle:-
- Addition of charged tRNA
- bonding between the amino
acids
- Translocation
- exit of uncharged tRNA
from E site

18. Termination
 Termination codons:-
- UAA, UAG, UGA
 Releasing Factors:-
- RF1, RF2.

20. Summary
 Formation of initiation complex
- binding of 30s subunit to tRNA
- binding of 50s subunit(70 s complex)
 Elongation:-
- addition of new amino acids
 Termination:-
- Binding of Releasing factors.