Genetic Code and Protein Synthesis

AUG

• UAA
• UAG
• UGA

One amino acid can be coded for by multiple codons

• Three potential reading frames for any mRNA sequence
• Six potential reading frames for any DNA sequence (ds)

change in codon does not result in change in amino acid

change in codon results in change in amino acid sequence

Change results in stop codon

One or two nucleotide insertion or deletion throws the reading frame out of register, resulting in longer or shorter proteins

Allows one anticodon to base pair with several different codons

• 50S
• 30S

• 60S
• 40S

• Signals for bacterial initiation of protein synthesis
• Purine-rich sequence located upstream of the AUG codon
• Registers the reading frame

• A - aminoacyl
• P- peptidyl
• E- exit

Multiple ribosomes workong in a single mRNA strand

Inhibits prokaryotic 30S ribosomal subunit

Inhibit prokaryotic 50S ribosomal sub unit