Biology Exam Preparation Portal. Preparing with U 4 ur exams...

Functions of Prokaryotic Initiation Factors

Protein synthesis in E.coli (bacteria) begins by the association of one 30S ribosomal subunit, an mRNA molecule, fMet-tRNA, three proteins known as Initiation Factors (IF) and guanosine 5 triphosphates (GTP). These  molecules constitute the 30S pre initiation complex.

Initiation of Protein synthesis in Prokaryotes

Initiation Factors (IF): Proteins that are required for the initiation of a new polypeptide chain.
  • Prokaryotic Initiation Factors (PIF): PIF-1 , PIF-2 , PIF-3


    Prokaryotic Initiation Factors
    (PIF)
    Mass
    (Dalton)
    Functions

    PIF-1


    8100

    Stimulates activity of IF2 and IF3; increases the affinity of the 30 S subunit for other factors.


    PIF-2

    97300

    Kinetic effector of 30s initiation complex formation; favours binding of amino acyl tRNAs with blocked αNH2 groups (formylmethionine-tRNA fMet); positions of fMet-tRNA fMet in P site of ribosome.

                   
                    PIF-3

    20700

    Kinetic effector of 30 S initiation complex formation; shifts equilibrium 70S =30S+50S to the right side, thereby ensuring provision of free 30 S ribosomal subunit for initiation.


Sharing is Caring ..... Please take 5 seconds to Share. Thank you...

0 comments:

Post a Comment

We love to hear from you! Leave us a comment.

© Biology Exams 4 U, AllRightsReserved.***Best viewed in Google Chrome and Mozilla firefox***

Maintained by BiologyExams4U.com