Principles of Biochemistry

7.5.1.Translation

7.5.1.Translation or Protein synthesis Initiation

The initiation of protein synthesis in human cells begins when mRNA attaches itself to the surface of a small ribosomal subunit such that its first codon, which is always the initiating codon AUG, occupies a site called the P site(peptidyl site).

An activated tRNA molecule with anticodon complementary to the codon AUG attaches itself, through complementary base pairing the AUG codon.

The resulting complex then interacts with a large ribosomal subunit to complete the formation of an initiation complex. Since the initiating codon AUG codes for the amino acid methionine, the first amino acid in a developing protein chain will be N-formyl methionine.