in depth elongation of translation

what is required for elongation other than the ribosome?

elongation factors

step 1

Met-tRNA_i^met bound to the P site (only tRNA that can bind to P site)

second amino acyl tRNA into ribosome (in association with EF1-GTP) and binds to the A site

EF1 also know as EF-Tu

step 2

tRNA anticodon base pairs with mRNA codon

EF1-GTP complex hydrolysed causing conformational change — amino acyl tRNA is tightly bound

3’ end of tRNA in A site is positioned close to 3’ end of tRNA in P site

step 3

alpha amino group in A site reacts with carboxyl group in P site forming a peptide bond between the amino acids

reaction catalysed by large rRNA

step 4

ribosome translocates downstream by one codon

regulated by hydrolysis of GTP in EF2-GTP (also known as EF-G)

amino acid in P site moves to E site

amino acid in A site moves to P site

step 5

translocation returns the ribosome conformation to step 2

tRNA in E site is ejected

A site is empty and able to accept an incoming amino acyl tRNA-EF1-GTP complex

cycle continues (2-5) until stop codon is reached