translation in prokaryotes and eukaryotes in details , with newest informations available with proper diagram

1. Presented by –
Dwijottam Sarma Bordoloi (17/BBT/20)
Ashish Pratim Mahanta (17/BBT/60)
Course : Biotechnology
Dept. Of Applied Biology

2. CONTENTS
1. Introduction
2. Translation in Prokaryotes
3. Translation in Eukaryotes
4. Differences between Prokaryotic and Eukaryotic translation
5. Conclusion
6. References

3. INTRODUCTION
 Translation process by which mRNA directs protein synthesis
with the assistance of tRNA.
 Last and most important phase of Central Dogma.
 Process is somewhat similar despite having certain differences in
case of both prokayotes and eukaryotes.
 mRNA is decoded in a ribosome to produce a specific sequence
of amino acids.
 Has 3 steps: (i) Initiation, (ii) Elongation, (iii) Termination

4.  Takes place from 5’ to 3’ direction.
 Elements involved :
(1) mRNA
(2) tRNA
(3) Ribosome
(4) Amino acids
(5) Translation factors [IF’s, Ef’s, RF’s]

5. TRANSLATION IN PROKARYOTES

6. 1.Initiation :
(a) tRNA charging – Addition of adenylylated amino acid to tRNA
Adenylylation of amino acid
Transfer of adenylylated a.â to tRNA
Transfer of adenylylated
a.â to tRNA
Aminoacyl
tRNA
synthetase

7. (b) Initiation complex formation –
30s initiation complex
70s initiation complex
INITIATION FACTORS
INVOLVED :
IF1, IF2 (GTPase
activity), IF3

9. 2. Elongation :
Elongation factors
involved –
EF-TU, EF-G, EF-Ts (all
GTPase proteins)
EF-TU attach to amino acyl
tRNA
tRNA attach to A site, EF-TU
bind to EF-TU binding site of
ribosome
EF-TU hydolyses GTP to GDP
and Pi
Codon-Anticodon bond is
formed
EF-TU fall off, carrying GDP
EF-Ts hydrolyses its GTP to
release energy to form bond
between GDP and a Pi and
make GTP again in the EF-TU
that fell off

10. Peptidyl
transferase

12. 3. Termination :
Occurs when a stop codon (UAA, UAG,UGA) is reached.
Termination factors
involved – RF1, RF2,
RF3, RRF
(also EF-G and IF3)
[RF1 recognizes UAA
and UAG, RF2
recognizes UAA and
UGA]

13. RF3 comes and bind to 50s subunit, contains GDP
RF1 detches from A site, energy is released, GTP is formed
A site free
RRF binds to A site; EF-G binds to ribosome to translocate
IF3 attach to E site
50s subunit dissociates
RRF signals the release of mRNA

15. TRANSLATION IN EUKARYOTES

16. 1. Formation of 43 s
Preinitiation complex
•eIF3 & eIF5 binds to exit (E) site.
•eIF1 blocks Amino acyl tRNA addition (A) site.
•eIF2 carrying GTP binds to met tRNA and get attached to
the peptide bond formation (P) site.
INITIATION

17. 2. Attachment of mRNA
•eIF4 complex (A/G/E/B/F) will bring and attach to mRNA (5` methylated guanine capping with
eIF4E )
•Poly A tail is folded back to form loop like structure.

18. 3. Scanning for
the START
codon
•Poly A tail moves to recognize the START
codon for the arrachment with tRNA .

19. 4. Assembly of large subunits
•eIF5B along with GTP carries and 60s subunit of RNA & get it attached to tRNA removing
eIF1 , eIF5 , eIF3 , eIF2 – GDP.

20. Elongation by EF1A

21. Cotranslational translocation
•Eukaryotes has
compartmentalization , different
organelle system ; for delivery of a
protein to the distinct organelle
need to add / modify/ fold them
which needs so much time ; to
consume less they do co-
translational translocation (
insertion of polypeptide chain into
ER lumen)
•First 10-20 polypeptide acts as signal
sequence will attract receptor
protein (SRP)
•SRP binds to SRP receptor found in
RER translocon channel.
•Ribosome near translocon channel
start adding more no. of amino acid
and insert polypeptide to ER lumen
•Polypeptide chains are restricted by
signal peptidase.

22. Post translocation Modification
•Protein should be modified cause it is very important as different organelle
take protein in different forms.
•Many chemical modifications takes place in GOLGI BOGY.

23. TERMINATION
•eRF3(hbs1) or eRF1(Dom34) along with GTP binds to the A site and terminate the
polypeptide chain hydrolysing GTP to GDP along with a water molecule.
•Rli 1 factor carries ATP which binds to ERF3/ERF1 hydrolyses and ribosome
recycling takes place.

24. DIFFERENCES
P
PROKARYOTES EUKARYOTES
1. 70s ribosome is involved.
2. Transcription and translation take
place simultaneously.
3. Translation is polycistronic.
4. Initiator protein – f-Met
5. Requires 3 release factors (RF1,
RF2, RRF)
6. Rate : 20 a.ȃ/sec
7. No modification of polypeptide
chain take place.
1. 80s ribosome is involved.
2. Transcription and translation don’t
take place simultaneously.
3. Translation is monocistronic.
4. Initiator protein – Met
5. Requires 2 release factors (eRF1,
eRF3)
6. Rate : 1 a.ȃ/sec
7. Modification of polypeptide chain
take place in golgi bodies

25. CONCLUSION
 Translation involves 3 phases namely Initiation,
Elongation and Termination, be it Prokaryotes or
Eukaryotes.
 Despite having differences in both of the translation
types, they are functionally very similar and their
ultimate goal is the same, i.e. To make proteins.
 Proteins are the crucial elements that our body uses
all throughout the life cycle and they are synthesis
solely by the process of translation.

26. REFERENCES
Websites –
www.wikipedia.org/wiki/translation
www.youtube.com/shomu’s_biology
www.softschool.com/science/biology
Book –
Life Sciences, Fundamentals and Practice – I (Fifth edition)
Pathfinder publication, New Delhi, India
By Pranav Kumar and Usha Mina