codon 2
(A
R
G)
codon 3
(G
L
Y)
codon 4
(SE
R
)
codon 5
(PRO)
codon 6
(TH
R
)
codon 7
(Stop)
codon 1
(f-MET/
Sta
r
t)
5'
3'
A U G
C G
C
G G A
U C C
C C C
A C C
U G A
X X X
X X X
U A C
f-met
An initiation complex to begin translation forms when a 30S ribosomal
subunit attaches to the ribosomal binding site (XXXs) located at the 5'
end of the mRNA and a formyl-methionyl (f-met) tRNA with a UAC
anticodon hydrogen bonds with the start codon AUG on the mRNA.
mRNA
30S ribosomal
subunit
f-met tRNA
50S ribosomal
subunit