Question

Some elongation factors are evolutionary related to the G-proteins involved in signal transduction. Provide a possible reason why this is the case.

Answer 1

The elongation factors and the G proteins are evolutionary related. Both of them utilize the high energy molecule GTP to initiate a cascade of signal transductionn events.

Where, G proteins are confined to the G protein coupled receptors present on the cell surfaces receive signals outside cell, take up GTP, undergo conformational change and activate the second messangers, to transduce intracellularly, the elongation factors are present in prokaryotes, that are specific to the regulation of protein translation from mRNA. These factors also make use of the energy obtained from GTP. The types of elongation factors include:

• EF-Tu
• EF-G
• EF-Ts
• EF-P

Of the four mentioned elogation factors all are invloved in the protein translation inn prokaryotes where, and also EF-Tu is itself a G protein that catalyzes the binding of aminoacyl-tRNA to the ribosome and facilitates the selection and binding aa-tRNA to ribosome. The significance of its role in translation can be attributed to the highly conserved sequence of this protein in prokaryotes.

As eukaryotes are themselves originated from prokaryotes, and the with sequence of these elongation factors being remained as conserved from the ancient times, the G proteins share an evolutionary relationship with the elongation factors.