Ribosome intiation

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Ribosome Initiation is the first step in the translation of mRNA to a protein. It requires initiation factors IF1, IF2 and IF3 as well as GTP for energy and an initiator tRNA known as fMet-tRNAfMet[1].  Initiation in prokaryotes occurs as follows:

  1. IF1 and IF3 bind to the free 30S subunit of the 70S ribosome.
  2. A GTP/IF2 complex then binds to the 30S subunit.
  3. The 30S subunit then binds to the 16S complementary region of the mRNA strand.
  4. A charged initiator tRNA can now bind which causes the release of IF3.
  5. The 50S subunit binds forming the ribosome, displacing IF1 and IF 2 and hydrolysing GTP to GDP. This step is the energy consuming step[2].

References

  1. Berg J, Tymoczko J L, Gatto G J, Stryer L. Biochemistry. 8th ed. New York. W. H. Freeman and Company. 2015
  2. Berg J, Tymoczko J L, Gatto G J, Stryer L. Biochemistry. 8th ed. New York. W. H. Freeman and Company. 2015