Number of Initiation Factor IF2 molecules per ribosome

Value 0.3 molecules/ribosome Range: Table - link molecules/ribosome
Organism Bacteria Escherichia coli
Reference Bremer, H., Dennis, P. P. (1996) Modulation of chemical composition and other parameters of the cell by growth rate. Neidhardt, et al. eds. Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd ed. chapter 97 Table 4
Primary Source Howe JG, Hershey JW. Initiation factor and ribosome levels are coordinately controlled in Escherichia coli growing at different rates. J Biol Chem. 1983 Feb 10 258(3):1954-9PubMed ID6337147
Method Cells were grown in media containing [35S]sulfate and different carbon sources, and harvested during mid-exponential phase after about 10 generations of balanced growth. Initiation factors (IF), elongation factors (EF), and a number of ribosomal proteins were identified unambiguously in gel patterns following two-dimensional polyacrylamide gel electrophoresis.
Comments IF2 binds to an initator tRNA and controls the entry of that tRNA into the ribosome. IF2, bound to GTP, binds to the 30S P site. After associating with the 30S subunit, fMet-tRNAf binds to the IF2 then IF2 transfers the tRNA into the partial P site. When the 50S subunit joins, it hydrolyzes GTP to GMP and PPi, causing a conformational change in the IF2 that causes IF2 to release and allow the 70S subunit to form.
Entered by Uri M
ID 104063