Initiation, Elongation, and Release Factors in Translation

bacterial IF1 and IF3

Prevent the association between small and large ribosomal subunits and favor their dissociation.

eukaryotic equivalents of bacterial IF1 and IF3

eIF1, eIF3, and eIF6.

bacterial IF2

Promotes the binding of the initiator tRNA to the small ribosomal subunit.

eukaryotic equivalent of bacterial IF2

eIF2.

bacterial IF4

Not applicable in bacteria; in eukaryotes, eIF4 recognizes the 7-methylguanosine cap at the 5′ end of mRNA and facilitates mRNA binding to the small ribosomal subunit.

role of eIF5 in eukaryotic translation

Helps dissociate initiation factors to allow the two ribosomal subunits to assemble.

bacterial EF-Tu

Binds tRNAs and delivers them to the A site.

eukaryotic equivalent of bacterial EF-Tu

eEF1α.

role of bacterial EF-Ts

Acts as a nucleotide exchange factor for EF-Tu.

eukaryotic counterpart of EF-Ts

eEF1βγ, which serves as the nucleotide exchange factor for eEF1α.

bacterial EF-G

Required for translocation of the ribosome during elongation.

eukaryotic counterpart of EF-G

eEF2.

bacterial RF1 and RF2

Recognize stop codons and trigger the cleavage of the polypeptide from the tRNA.

eukaryotic equivalent of RF1 and RF2

eRF1.

bacterial RF3

A GTPase involved in translation termination.

eukaryotic equivalent of RF3

eRF3, also a GTPase involved in termination.