Final answer:
Mutation of eIF-2 to eliminate GTP hydrolysis impairs translation initiation by preventing proper release of initiation factors and 60S ribosomal subunit binding, thus impairing elongation. Increased phosphorylation of eIF-2 is seen in neurodegenerative diseases and obstructs protein synthesis by blocking translation initiation.
Step-by-step explanation:
If a scientist mutates eIF-2 to eliminate its GTP hydrolysis capability, the mutated form of eIF-2 would impair the initiation phase of translation. During the initiation phase of translation, the eIF-2 protein must bind to GTP. This GTP-bound eIF-2, in turn, associates with the initiator tRNA and the small 40S ribosomal subunit to form a ternary complex that then binds to mRNA. The binding of the large 60S ribosomal subunit to this complex triggers the hydrolysis of GTP to GDP on eIF-2, which causes a conformational change necessary for the release of initiation factors and allows translation to proceed. Without the ability to hydrolyze GTP, the initiation complex cannot undergo this necessary structural change, and thus, it will not properly release the initiation factors to allow the 60S ribosomal subunit to bind. Consequently, translation cannot proceed normally, which leads to the answer: b) Elongation of translation would be impaired.
An increase in phosphorylation levels of eIF-2 has been observed in patients with neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's. Phosphorylation of eIF-2 leads to a conformational change that prevents binding to GTP, thus impeding the formation of the initiation complex necessary for the translation to occur. Therefore, we deduce that an increase in eIF-2 phosphorylation can disturb protein synthesis, possibly blocking the translation of certain proteins, which could contribute to disease pathology.