Prokaryotic initiation factor-3
Encyclopedia
Prokaryotic initiation factor-3 is a prokaryotic initiation factor.
IF3 is not universally found in all bacterial species but in E. coli
it is required for the 30S
subunit to bind to the initiation site in mRNA
. In addition, it has several other jobs including the stabilization of free 30S subunits, enables 30S subunits to bind to mRNA and checks for accuracy against the first aminoacyl-tRNA
. It also allows for rapid codon-anticodon pairing for the initiator tRNA
to bind quickly to. IF3 is required by the small subunit to form initiation complexes, but has to be released to allow the 50S
subunit to bind.
IF3 is not universally found in all bacterial species but in E. coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
it is required for the 30S
30S
30S is the smaller subunit of the 70S ribosome of prokaryotes. It is a complex of ribosomal RNA and ribonucleoproteins that functions in mRNA translation...
subunit to bind to the initiation site in mRNA
Messenger RNA
Messenger RNA is a molecule of RNA encoding a chemical "blueprint" for a protein product. mRNA is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein...
. In addition, it has several other jobs including the stabilization of free 30S subunits, enables 30S subunits to bind to mRNA and checks for accuracy against the first aminoacyl-tRNA
Aminoacyl-tRNA
Aminoacyl-tRNA is tRNA to which its cognated amino acid is adhered. Its role is to deliver the amino acid to the ribosome where it will be incorporated into the polypeptide chain that is being produced...
. It also allows for rapid codon-anticodon pairing for the initiator tRNA
Transfer RNA
Transfer RNA is an adaptor molecule composed of RNA, typically 73 to 93 nucleotides in length, that is used in biology to bridge the three-letter genetic code in messenger RNA with the twenty-letter code of amino acids in proteins. The role of tRNA as an adaptor is best understood by...
to bind quickly to. IF3 is required by the small subunit to form initiation complexes, but has to be released to allow the 50S
50S
50S is the larger subunit of the 70S ribosome of prokaryotes. It is the site of inhibition for antibiotics such as macrolides, chloramphenicol, clindamycin, and the pleuromutilins. It includes the subunits 5S and 23S.-Structure:...
subunit to bind.