1. PRESENTED BY
ENA ATHAIDE
MSC-II ,BIOCHEMISTRY
INSTITUTE OF SCIENCE, MUMBAI
TRANSLATION
Initiation and Activation

2. Central Dogma

3. Why Translation ?
Translation converts an mRNA strand into a
chain of amino acids to form Protein

4. TRANSLATION
 The term Translation is used to represent the
Biochemical translation of 4 Letter language (A,G,C,U) to
20 letter language of Proteins.
 The sequence of amino acids in the protein synthesized
is determined by the nucleotide sequence of mRNA.
 Genetic code: 3 (triplet)base sequences in m RNA that
acts as code words for amino acids in proteins.(codons).
 Dictionary of nucleotide bases that determines the
sequence of amino acids.

5. GENETIC CODE

6. Components essential in Translation
 Amino acids : 20 amino acids ( 10 essential
)
 Ribosomes
•large and complex molecular machine
•Consist of 2 subunits
• small ribosomal subunit reads the mRNA.
• large subunit joins amino acids to form
a polypeptide chain.
•70 S – Prokaryotes,80 S - Eukaryotes

7. Sites for tRNA binding in Ribosomes

8. Components essential in Translation
 m RNA : contain information required for
synthesis of protein present on m RNA.
 t RNA : They carry a.a and hand them over
to growing peptide chain.
 ATP,GTP , Protein Factors

9. STAGES OF TRANSLATION
Activation
Initiation
Elongation
Termination

10. Activation of amino acids
Each amino acid has a specific tRNA
There is specific aminoacyl-tRNA-synthetase for each AA
Aminoacyladenilate + tRNA  aminoacyl-tRNA + AMP

11. Structure of tRNA

12. Initiation of Translation
• The translation complex is assembled
at the beginning of the mRNA coding
sequence
• Complex consists of:
-Ribosomal subunits
-mRNA template to be translated
-Initiator tRNA molecule
-Protein initiation factors

13. Initiator tRNA
• First codon translated is usually AUG
(met)
• The initiator tRNA recognizes initiation
codons
-Bacteria: N-formylmethionyl-tRNA
-Eukaryotes: Methionyl-tRNA

15. Ongoing Research
Study supports flawed protein synthesis theory of
autism
A new study bolsters the idea that overactive
protein synthesis, or translation, contributes to
autism. The findings ,also show that dampening
a single overabundant protein, neuroligin-
1 (NLGN1), reverses both abnormal brain activity
and social deficits in mice with excess
translation.
A number of mouse models of autism-related
disorders, including fragile X syndrome and
tuberous sclerosis complex, show excessive

16.  Study supports flawed protein synthesis theory of
autism
Ongoing Research

17. References
 Prescot,Harley,Kein.Microbiology,McGraw.Hill
International edition.pg:276-285.
 P Russel,B Chase.iGenetics:A Molecular
Approach,4th edition.pg:147-148
 U.Satyanarayana,U.Chakrapani.Biochemistry,3rd
edition,pg:555-557.
 Gkogkas CG, Khoutorsky A, Ran I, Rampakakis
E, Nevarko T, Weatherill DB, Vasuta C, Yee
S, Truitt M, Dallaire P, Major F, Lasko P, Ruggero
D, Nader K,Lacaille JC, Sonenberg N. Autism-
related deficits via dysregulated eIF4E-dependent
translational control. Department of Biochemistry &
Goodman Cancer Research Centre, Nature. 2013