Translation of MRNA to Proteins - Essay Example

The translation of mRNA to Proteins The translation of mRNA to Proteins The translation of mRNA starts with the formation of mRNA, which is a complex molecule. The initiation proteins join to the smaller sub-units of the ribosome. The initiation proteins are of three types, which include IF1, IF2 and IF3. The tRNA and the preinitiation complex formed combine with the mRNA forming the initiation complex (Clancy and William, 2008).After the initiation complex is formed on the mRNA, the larger subunits of ribosome bind to the initiation complex, which causes the Ifs (initiation factors) to be released.

There are three sites where the TRNA binds to the ribosome larger subunits. This include the A(amino acid) site, where the aminoacyl-tRNA anticodon base combine with the mRNA codon ensuring the actual amino acid is included in the growing polypeptide chain. The second site is the P (polypeptide) site where the amino acid is moved from its TRNA to the growing chain of polypeptide. The third site is the E (exit) site where the empty TRNA stays before it is released back to the cytoplasm to combine with another amino acid and the process is repeated (Clancy and William, 2008).

The next phase in the translation process is the elongation phase. In this phase, the ribosome moves with the mRNA in a direction referred to 5’ to 3’ direction, which needs the elongation factor G. The tRNA that corresponds to the second codon bids to the site A, a step that requires the guanosine triphosphate (GTP), which provides energy for the process and the elongation factors EF-Tu and EF-Ts. After the TRNA- amino acid complex is in site A, GTP is broken down to form guanosine diphosphate (GDP) and released together with EF-Tu so as to be recycled by Elongation factor EF-Ts for the next process (Clancy and William, 2008).

The next process is the formation of peptide bonds between the first and second adjacent amino acid through the activity of peptidyl transferase. Once the peptide bond is formed, the ribosome translocates causing the tRNA to occupy the E site. The tRNA is released to the cytoplasm to combine with another amino acid. Additionally, the site A remains empty and is ready to accept the mRNA for the next codon. This process occurs repeatedly until all the codons in the mRNA are read by the TRNA molecules, and the amino acids attached to the tRNA are joined to the chain of the growing polypeptide in the appropriate order.

As soon as this takes place, translation process is terminated; the nascent protein is released from the ribosome and the mRNA (Clancy and William, 2008).ReferencesClancy, Suzanne and William Brown. (2008). Translation: DNA to mRNA to Protein. Retrieved From: http://www.nature.com/scitable/topicpage/translation-dna-to-mrna-to-protein-393