Translation initiation factor aIF-2, bacterial-like (IPR000178)

Short name: TF_IF2_bacterial-like

Overlapping homologous superfamilies

Family relationships


Initiation factor 2 (IF-2) (gene infB) [PMID: 1805969] is one of the three factors required for the initiation of protein biosynthesis in bacteria. IF-2 promotes the GTP-dependent binding of the initiator tRNA to the small subunit of the ribosome. IF-2 is a protein of about 70 to 95 Kd which contains a central GTP-binding domain flanked by a highly variable N-terminal domain and a more conserved C-terminal domain. Bacterial IF-2 is structurally and functionally related to eukaryotic mitochondrial IF-2 (IF-2(mt)) [PMID: 7829522] as well as to algal and plants chloroplast IF-2 (IF-2(chl)). Both IF-2(mt) and IF-2(chl) are encoded by nuclear genes and are produced as precursor proteins with a transit peptide. An exception are red algae where IF-2(chl) is encoded by the plastid genome [PMID: 8219057].

This model discriminates eubacterial (and mitochondrial) translation initiation factor 2 (IF-2), encoded by the infB gene in bacteria, from similar proteins in the Archaea and Eukaryotes. In the bacteria and in organelles, the initiator tRNA is charged with N-formyl-Met instead of Met. This translation factor acts in delivering the initator tRNA to the ribosome. It is one of a number of GTP-binding translation factors recognised by the pfam HMM GTP_EFTU.

GO terms

Biological Process

GO:0006413 translational initiation

Molecular Function

GO:0005525 GTP binding
GO:0003743 translation initiation factor activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns