Question: EF-Tu binds all aminoacyl-tRNAs with approximately equal
affinity so that it can deliver them to …
EF-Tu binds all aminoacyl-tRNAs with approximately equal
affinity so that it can deliver them to the ribosomes with the same
efficiency. Based on the experimentally determined dissociation
constants for EF-Tu and correctly charged and mischarged
aminoacyl-tRNAs in the table below, explain how the tRNA-EF-Tu
recognition system could prevent the incorporation of the wrong
amino acid during translation.
Aminoacyl-tRNA |
Dissociation constant (nM) |
Ala-tRNAAla |
6.2 |
Gln-tRNAAla |
0.05 |
Gln-tRNAGln |
4.4 |
Ala-tRNAGln |
260 |
The binding of appropriately charged tRNA
(Ala-TrnaAla and Gln-tRNAglu) to EF-Tu with
similar affinity