Question

A scientist mutates eIF-2 to eliminate its GTP hydrolysis capability. How would this mutated form of eIF-2 alter translation?

Answer 1

Answer-

According to the given question-

We know that Transcription occur inside the nucleus in eukaryotes and after that RNA molecule transported from nucleus to cytoplasm where the information present in mRNA are translated into protein. The translation is Controlled by the RNA molecule. Translation starts when translation initiation complex  formation takes place.

When met-tRNAi binds to small subunit or 40S of ribosome the initiation started. A protein called eukaryotic initiation factor-2 or eIF-2 is a type of protein initiation factor, brought tRNA to 40S ribosome. eIF-2 protein first binds to guanosine triphosphate or GTP molecule and after that tRNA-eIF2-GTP complex attaches to 40S ribosome subunit. Several initiation factors have the capability to recognize mRNA   5′ cap and some proteins bind to poly-A tail mRNA to form a loop like structure.  eIF4F or cap-binding protein then brings both mRNA complex and tRNA-eIF2-GTP- 40S ribosome complex together after that this complex scan  mRNA to find AUG or start codon. after that the initiator tRNA anticodon and AUG aligned causing GTP hydrolysis as well as release of initiation factors and  large subunit of ribosome i.e. 60S ribosomal attaches to translation complex.

eIF-2 binding with RNA is regulated by phosphorylation after  phosphorylation it is unable to bind with GTP. sue to which initiation complex is unable to form correctly and this effect the translation because  large ribosomal subunit or 60S ribosomal unable to bind with the mRNA transcripts. but when eIF-2 is unphosphorylated this causes formation of translation initiation complex and leads to normal translation.