Introduction Components of protein synthesis Translation in eukaryotes 1.initiation 2.elongation 3.Termination Conclusion references

1. ,
By
KAUSHAL KUMAR SAHU
Assistant Professor (Ad Hoc)
Department of Biotechnology
Govt. Digvijay Autonomous P. G. College
Raj-Nandgaon ( C. G. )

2.  Introduction
 Components of protein synthesis
 Translation in eukaryotes
 1.initiation
 2.elongation
 3.Termination
 Conclusion
 references

3.  Protein synthesis is the process in which cells build protein .
 Protein synthesis consist of two main events, transcription and translation.

4.  The process by which protein is synthesized is called
translation. because the language of nucleic acid base is
translated into language of amino acid.

5.  The main components of protein biosynthesis are:
 Activation of Amino acid.
 Ribosome
 messenger RNA.
 Transfer RNA.
 Energy source & protein factor.

6.  Ribosome are the site for protein synthesis.
 Prokaryote- 70S & Eukaryote- 80S
 The ribosome has 2 site. (1)A site (2) P site.
 A site is for binding of the aminoacyl t RNA & P site is
for binding of peptidyl t RNA.
 Eukaryotes contain A, P & E site.
 A-site is called= acceptor site , P is donor site & E is exit
side.

8.  The specific information which are required for protein
synthesis is present on mRNA.
 the DNA has passed on the genetic information in the
form of codans to the mRNA to translate into a protein
sequence.

9.  It play the central role in translation.
 Amino acid is covalently bound to the tRNA at the 3`-end
 Each tRNA has 3 nucleotide base sequence ( anticodon)
which is responsible to recognize the
codon(complimentary bases) of mRNA for protein
synthesis.

10.  both ATP &GTP required for the supply of energy in
protein synthesis.
 The process of translation involve a number of protein
factors . They are important for initiation, elongation &
termination.

11.  Group of 3 nucleotide that
specifies an amino acid is known
as codon
 Amino acids are the monomers
which are polymerized to
produced protein.
 Aminoacyl –t RNA synthetase
activate amino acids by covalently
linking them to t RNA .

12.  It divided into 3 major stage:
 1. Initiation.
 Elongation.
 Termination.

13.  it involve 10 eukaryotic initiation factors(eIFs)
 Initiation can be divided into 4 steps:
 1.ribosomal dissociation.
 2. formation of 43S preinitiation complex.
 3. formation of 48S initiation complex.
 Formation of 80S initiation complex.

14.  The 80S ribosome dissociates to form 40S &60S subunits. Then
2 initiating factors eIF-3& eIF-1 bind to the 40S subunit.& block
its re association with 60S subunits.
 eIF-3 &eIF-1 called anti association factor.
80S
40s
60S

15.  Met- tRNA &eIF-2 bound to GTP & attaches to 40S
ribosomal subunit to form 43S preinitiation complex.
 EIF-3 & eIF-1A stabilizes this complex.
 Met-tRNA is involved to the binding of initiating codon
AUG.
Met-tRNA GTP 40s 43S

16.  The binding of mRNA to the 43S preinitiation complex
results in the formation of 48S initiation complex.
 In eukaryote recognition sequence of initiation codon is
called as kozak consensus sequence.
 In prokaryote shine- dalgarno sequence.
mRNA 43s 48S

17.  48S initiation complex binds to 60S ribosomal subunit to
form 80S initiation complex. The binding involve the
hydrolysis of GTP.in this step eIF-5 is involved.

18.  It may be divided into 3 steps:
 1binding of aminoacyl t-RNA to A site.
 2peptide bond formation.
 3Translocation.

19.  The 80S initiation complex contain met-tRNA in the P-
site & the A-site is free .then another aminoacyl t-RNA is
placed in the A-site.
 Elongation factor-1 involve in this process &energy
supply by GTP.
 When the aminoacyl t-RNA is placed in the A-site then
EF-1&GTP are recycled to bring another aminoacyl t-
RNA.

20.  The enzyme peptydyl transferase catalyses the formation of
peptide bond.
 There is no energy require for the Peptide bond formation because
amino acid in the aminoacyl t-RNA is already activated.
 The growing peptide chain attach to the tRNA in A-site then
peptide bond formation take place.

21.  As the peptide bond formation occurs, the ribosome
moves to the next codon of mRNA towards 3`end the
process is called translocation.
 It require EF-2 & GTP.
 GTP gets hydrolyzed &supply energy to mRNA then EF1
&GTP complex recycles for translocation. After the
process tRNA moves into E-site from where it leaves the
ribosome.

23.  Termination of the protein synthesis occurs of the 3 stop
codon UAA, UGA, UAG .they enters to A- site of the
ribosome. There are no t-RNA molecule that recognize
the stop codons.
 A release factor protein bind to the A-site & cause
hydrolysis. The completed polypeptide is release
&ribosome separated into small subunits for the
preparation of next round of protein synthesis.

25.  It is the most essential process for the conversion of mRNA to
protein without which no gene would be able to code any
functional protein.
 it forms the basis of many cellular and metabolic processes.
 transcription is the initial level at which gene expression is
controlled the translation of mRNA is also regulated in both
prokaryotic and eukaryotic cells.

26. BOOK NAME EDITION WRITER
Biochemistry 3RD edition U.satyanarayana
Cell & Molecular Biology 6th edition Gerald Karp
INTERNET TIME
www.authorstream.com 8/03/2013 6:30pm