1
tRNA (provides amino acids)
Ribosome (complex of rRNA
and proteins where
tranlation occurs)
Flow of genetic information --- the “Central Dogma”
DNA
RNA
Protein
Replication
Transcription
Translation
mRNA (primary sequence)
Lecture 50: Translation (protein synthesis)
Today’s lecture: Text pp. 1027-1044
Preprinted lecture notes 76-85
Download from
http://biochem.med.ufl.edu/coursetemp.php?cid=44
or
http://www.mbi.ufl.edu/facilities/msg/bch4024-notes.html
tRNA is the adaptor molecule for RNA
Æ
amino acid
¾
Each tRNA contains a
nucleotide triplet or “anti
codon” complimentary to the
mRNA for a particular amino
acid
¾
Aminoacyl-tRNA synthetase
attaches a particular tRNA to
its corresponding amino acid
¾
tRNA has extensive self-
complimentarity and is much
more stable than mRNA
Phenylalanine tRNA
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2
Protein synthesis: activation of amino acids
a) Aminoacyl-tRNA
synthetase binds amino
acid + ATP to yield
enzyme-bound
adenylated amino acid
b)
tRNA binds to the
adenylated a.a.-
synthetase complex and
the amino acid is
transferred to the 2’ or 3’
OH of the 3’-terminal
residue of the tRNA
c) Activation….
The ester bond in aatRNA has a free energy of hydrolysis ~ ATP terminal
PO
4
d) Requisite specificity of aatRNA synthetases
1) for tRNA (>20)
2) for amino acid (~20)
∴

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- Fall '08
- ALLISON
- Biochemistry, DNA, RNA
-
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