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Which of the following is true regarding the interaction of prokaryotic EF-Tu with aminoacyl-tRNAs?

a) EF-Tu binds to aminoacyl-tRNA in the A site
b) EF-Tu hydrolyzes GTP before binding to aminoacyl-tRNA
c) EF-Tu enhances the accuracy of translation
d) EF-Tu is directly involved in peptide bond formation

User Shoen
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1 Answer

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Final answer:

EF-Tu enhances the accuracy of translation by ensuring correct aminoacyl-tRNA and mRNA codon matching but is not directly involved in peptide bond formation, which is catalyzed by peptidyl transferase.

Step-by-step explanation:

Among the options provided regarding the interaction of prokaryotic EF-Tu with aminoacyl-tRNAs, the true statement is that c) EF-Tu enhances the accuracy of translation. EF-Tu is an elongation factor that plays a critical role in the translation process by ensuring that aminoacyl-tRNAs are correctly matched with the codons of the mRNA. EF-Tu, in its GTP-bound form, binds to the aminoacyl-tRNA and escorts it to the A site of the ribosome. Once the correct base pairing between the tRNA anticodon and the mRNA codon is confirmed, EF-Tu hydrolyzes its bound GTP to GDP, prompting a conformational change that leads to the release of EF-Tu-GDP, thus allowing the aminoacyl-tRNA to fully enter the A site and participate in peptide bond formation.

The peptide bond formation itself, however, is not directly catalyzed by EF-Tu but rather by the peptidyl transferase enzyme which is an integral part of the large ribosomal subunit. Therefore, while EF-Tu aids in ensuring the fidelity of translation by matching tRNAs to the correct mRNA codons, it does not play a direct role in the actual peptide bond formation. This is in contrast to the incorrect option 'd)', which suggests a direct involvement of EF-Tu in the peptide bond formation process, which is not the case.

User Adam Norberg
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