ZOOHCC - 501: Molecular Biology (Theory)



Unit 4: Translation 











    Proteins involved in translation



    Translation is the process by which genetic information in mRNA is used to
    synthesize a protein. It involves the coordination of many different
    proteins and RNA molecules. The proteins involved in translation can be
    broadly classified into three categories based on the stages of translation:
    initiation, elongation, and termination.



    Initiation factors: Proteins called initiation factors are involved in the
    assembly of the ribosome on the mRNA and the selection of the correct start
    codon. These include:



    IF1, IF2, and IF3: These proteins help to assemble the ribosome on the mRNA
    and stabilize the correct start codon in the ribosome's P-site.



    eIF1, eIF2, eIF3, and eIF4: These proteins are involved in the initiation
    of translation in eukaryotes.



    Elongation factors: Elongation factors help to add amino acids one by one
    to the growing polypeptide chain. These include:



    EF-Tu and EF-Ts: These proteins help to bring aminoacyl-tRNAs to the
    ribosome and ensure that the correct amino acid is added to the growing
    polypeptide chain.



    EF-G: This protein helps to translocate the ribosome along the mRNA.



    Termination factors: Termination factors are involved in the recognition of
    stop codons and the release of the polypeptide chain from the ribosome.
    These include:



    RF1 and RF2: These proteins recognize stop codons and trigger the release
    of the polypeptide chain from the ribosome.



    eRF1: This protein is the eukaryotic equivalent of RF1 and RF2.



    Explanation



    Proteins involved in the three stages of protein synthesis, initiation,
    elongation, and termination, are as follows:



    Initiation:



    The process of translation starts with the initiation stage where the
    ribosome assembles on the mRNA and selects the correct start codon. The
    following proteins are involved in the initiation stage:



    Initiation factors (IFs): IF1, IF2, and IF3 are proteins that help to
    assemble the ribosome on the mRNA and stabilize the correct start codon in
    the ribosome's P-site.



    Small ribosomal subunit: This subunit of the ribosome binds to the mRNA and
    scans for the start codon.



    Elongation:



    Once the ribosome has identified the start codon, the elongation stage
    begins, where amino acids are added one by one to the growing polypeptide
    chain. The following proteins are involved in the elongation stage:



    Elongation factors (EFs): EF-Tu and EF-Ts are proteins that help to bring
    aminoacyl-tRNAs to the ribosome and ensure that the correct amino acid is
    added to the growing polypeptide chain.



    Large ribosomal subunit: This subunit of the ribosome catalyzes the
    formation of peptide bonds between amino acids.



    Termination:



    The termination stage occurs when the ribosome reaches a stop codon on the
    mRNA, and the newly synthesized polypeptide chain is released. The following
    proteins are involved in the termination stage:



    Release factors (RFs): RF1 and RF2 are proteins that recognize stop codons
    and trigger the release of the polypeptide chain from the ribosome.



    Ribosome recycling factor (RRF): RRF helps to dissociate the ribosome from
    the mRNA and recycle its subunits for the next round of translation.



    Overall, protein synthesis is a complex process that involves the
    coordinated action of many proteins and RNA molecules.