One of the essential components for the initiation of protein synthesis. May protect N-formylmethionyl-tRNA(fMet) from spontaneous hydrolysis. Promotes N-formylmethionyl-tRNA(fMet) binding to the 30S pre-initiation complex (PIC) (PubMed:1764105, PubMed:20224578). Also involved in the hydrolysis of GTP during the formation of the 70S ribosomal complex. Upon addition of the 50S ribosomal subunit, IF-1, IF-2 and IF-3 are released leaving the mature 70S translation initiation complex. Component of the 30S ribosomal translation pre-initiation complex which assembles on the 30S ribosome in the order IF-2 and IF-3, IF-1 and N-formylmethionyl-tRNA(fMet); mRNA recruitment can occur at any time during PIC assembly. Part of the metY operon that extends to pnp (PubMed:2849753). A proteolyzed form, called IF2 gamma (begins with residue 290), can be detected during purification which has all the activities expected for this protein, although it is slightly less efficient than full-length protein. It is not clear if it exists in vivo. Essential, it cannot be deleted. The C-terminal region (residues 165-890) is sufficient for growth at 42 degrees Celsius, although it grows more slowly at 37 degrees and is cold-sensitive at 30 degrees Celsius (PubMed:1374802). When overexpressed partially suppresses the slow growth and decreased 70S ribosome phenotype of an rsgA knockout; RsgA may be involved in 30S ribosomal subunit biogenesis. Silent mutations of codon 158, which no longer function as alternative start codons, decrease beta isoform expression to 31 to 50%, the strongest mutation is GUG to GUC. Isoform alpha is approximately 2-fold more abundant than the combined beta isoforms. Optimal growth requires both alpha and beta IF2. Also called beta1. Also called beta2. Belongs to the TRAFAC class translation factor GTPase superfamily. Classic translation factor GTPase family. IF-2 subfamily.