Bacterial initiation factor-2 is a

bacterial initiation factor Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

. IF2 binds to an initiator tRNA and controls the entry of tRNA onto the ribosome. IF2, bound to GTP, binds to the

30S The prokaryotic small ribosomal subunit, or 30 S subunit, is the smaller subunit of the 70S ribosome found in prokaryotes. It is a complex of the 16S ribosomal RNA (rRNA) and 19 proteins. This complex is implicated in the binding of transfer R ...

P site. After associating with the 30S subunit, fMet-tRNA_f binds to the IF2 then IF2 transfers the tRNA into the partial P site. When the 50S subunit joins, it

hydrolyzes Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

GTP to

GDP Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is ofte ...

and P_i, causing a conformational change in the IF2 that causes IF2 to release and allow the 70S ribosome to form. Human

mitochondria A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is used ...

use a nuclear-encoded homolog, MTIF2, for translation initiation.

References

{{GTPases Molecular biology Protein biosynthesis Gene expression