Final answer:
Ribosome recycling termination involves GTP hydrolysis for the release of the polypeptide chain and the separation of ribosomal subunits after a stop codon is encountered.
Step-by-step explanation:
Ribosome recycling and termination consume energy through the hydrolysis of GTP. The process is triggered when a stop codon is encountered, and release factors RF1, RF2, and RF3 facilitate the release of the polypeptide chain and the dissociation of ribosomal subunits. To phrase a direct answer in two lines: Energy utilization in ribosome recycling termination primarily involves the hydrolysis of GTP for the release of the polypeptide and the disassembly of ribosomal subunits.
During the termination phase of protein synthesis, energy expenditure is necessary for the efficient disassembly of the translation machinery. As the ribosome stalls at stop codons (UAA, UAG, UGA), release factors recognize these codons, leading to P-site amino acid detachment and polypeptide release. Subsequent dissociation of 30S and 50S ribosomal subunits from the mRNA requires an additional GTP hydrolysis. This energy cost is a continuation of the investment during elongation, where each amino acid addition to the polypeptide chain also depends on GTP for tRNA charging, aminoacyl-tRNA delivery, and ribosomal translocation. The efficiency of this process is highlighted by the fact that E. coli can add a single amino acid in just 0.05 seconds. Thus, while the overarching process is rapid, it still incurs a significant energy cost, highlighting how the cell strategically uses its resources to ensure high-fidelity protein synthesis.