The ribosome turns a nucleic acid sequence into a protein sequence. Its small subunit checks each codon against the anticodon of an incoming tRNA. Its large subunit joins the new amino acid to the growing chain, using RNA alone as the catalyst. The two subunits then rotate against each other and the mRNA advances by one codon.
- Where
- All cells. Bacteria and archaea use 70S ribosomes; eukaryotes use 80S ribosomes in the cytosol and separate ribosomes in mitochondria and chloroplasts.
- Power
- GTP hydrolysis by EF-Tu and EF-G, plus the ester bond energy of aminoacyl-tRNA
12-17 amino acids per second
Elongation rate in E. coli
102-20 amino acids per second
Elongation rate across systems
710−3 to 10−4
Missense error rate per codon
11