- Aminoacyl tRNA synthetase enzymes activate amino acids through attaching them to ATP, forming aminoacyl adenylates. - The activated amino acids are then attached to specific transfer RNA (tRNA) molecules by aminoacyl tRNA synthetases. - This produces aminoacyl-tRNA, where each tRNA is charged with its cognate amino acid, serving as an adaptor molecule for protein synthesis.

1. AMINOACYL TRNA SYNTHETAGE AND
CHARGING OF TRNA
Presented by-
Luna Devi
Kaliabor College

2. INTRODUCTION
 Protein are giant molecules of utmost
biological importance because these not
only form the building material of the cell,
but act as enzymes controlling all the
biochemical reactions going on in the living
system and also control the expression of
phenotypic traits.
 Chemically protein is polymer of amino
acid. Only 20 amino acid are biologically
important and participate in the formation
of polypeptide chains of protein.
 These protein molecule synthesis in
ribosome. The whole process of protein
synthesis is called Central Dogma.
transcription
DNA RNA
REVERSE
TRANSCRIPTION
Protein
translation

3. THE RAW MATERIALS OF PROTEIN SYNTHESIS
 Ribosomes-Where protein synthesis occurs
 Amino acids-the the building blocks of protein
 MessengerRNA (mRNA)-where genetic
information encoded
 Transfer RNA (tRNA)-which decode the mRNA
 Some types of enzymes
 ATP, etc.

4. PROTEIN SYNTHESIS
 Protein synthesis has two completed in two
steps - transcription
translation
 In transcription mRNA molecules are
transcripted from the parent DNA molecule
and transcribed mRNA move out of the
nucleus to the ribosomes in the cytoplasm.
 In translation genetic information carried by
mRNA are determines the order of amino acid.

5. TRANSLATION
Translation subdivided into -
pre initiation stage
Initiation
Elongation
Termination

6. ………..
 In pre-initiation stage involves-
1. activation of amino acids
2. Attachment of activated amino acids
with tRNA

7. ACTIVATION OF AMINO ACIDS
 Amino acids in cytoplasm occur in inactive form
and they can not take in protein synthesis. Hence
these are activated by giving them energy. The
activation is facilitated through ATP, whose
molecules unite with the amino acids forming
highly reactive amino acid phosphate adenyl
complexes which are known as aminoacyl
adenylates. These process governs by specific
enzyme aminoacyl tRNA synthetage enzyme.
Amino acid + ATP AMP AA+ PP
Activating
enzyme
Pyrophosphate
Activated amino
acid

8. FIG: TRANSFER RNA MOLECULES

9. ATTACHMENT OF ACTIVATED AMINO ACIDS WITH
TRNA
 The enzyme bound activated amino acids,
aminoacyl adenylate, become attached to the
3' end of their respective tRNA molecules The
attachment is catalysed by the same enzymes,
aminoacyl transfer RNA aynthetases, that
catalyse activation of their amino acid. The
product thus formed is known as aminoacyl
transfer RNA (aminoacyl tRNA)
AA AMP+ tRNA AA tRNA + AMP

10. FIG: PROCESS OF AMINO ACID ACTIVATION BY
ENZYME AMINO ACYL TRNA SYNTHETASE

11. NOTE
 The specific amino acids join specific tRNA molecules.
This means that for 20 amino acid at least there are 20
different tRNA molecules and 20 different enzymes,
tRNA charged with cognate amino acid serves as an
adaptor molecule for decoding the information on
mRNA. Therefore, tRNA is also called adaptor RNA. The
RNA with attached amino acid is said to be acylated or
charged. The RNA molecule without an amino acid is
uncharged tRNA while with an correct amino acid, it is
called mischarged tRNA. There are no tRNA for
termination codons. Hence, synthesis of polypeptide
chain terminates at a codon for which there is no tRNA.