Editing domain (AT)

The post-transfer editing domain AT (Edit-AT) catalyses the removal of misacylated serine and glycine residues from the cognate acceptor stems of alanine and threonine: $ \text{Ser-tRNA}^\text{Ala} \xrightarrow{\text{Edit-AT}} \text{Ser} + \text{tRNA}^\text{Ala} $ $ \text{Gly-tRNA}^\text{Ala} \xrightarrow{\text{Edit-AT}} \text{Gly} + \text{tRNA}^\text{Ala} $ $ \text{Ser-tRNA}^\text{Thr} \xrightarrow{\text{Edit-AT}} \text{Ser} + \text{tRNA}^\text{Thr} $ Paralogs of Edit-AT exist at the N-terminal of [ThrRS](/class2/thr/), the C-terminal of [AlaRS](/class2/ala/), and in the form of the trans-acting factor AlaX, which also targets Ser-tRNA$^\text{Ala}$ (Dock-Bregeon et al. 2004, Beebe et al. 2008). This editing activity lowers the rate of serine-for-threonine, glycine-for-alanine, and serine-for-alanine mistranslations. The third kind (S $\rightarrow$ A) is known to cause profound problems in nature, and hence many systems have evolved to lower its rate of occurrence (Guo et al. 2009a, Schimmel 2011).

References

Schimmel, Paul. "Mistranslation and its control by tRNA synthetases." Philosophical Transactions of the Royal Society B: Biological Sciences 366.1580 (2011): 2965-2971. Guo, Min, et al. "Paradox of mistranslation of serine for alanine caused by AlaRS recognition dilemma." Nature 462.7274 (2009a): 808-812. Guo, Min, et al. "The C-Ala domain brings together editing and aminoacylation functions on one tRNA." Science 325.5941 (2009b): 744-747. Beebe, Kirk, et al. "Distinct domains of tRNA synthetase recognize the same base pair." Nature 451.7174 (2008): 90-93. Gomez, Miguel Angel Rubio, and Michael Ibba. "Aminoacyl-tRNA synthetases." Rna 26.8 (2020): 910-936. Dock-Bregeon, Anne-Catherine, et al. "Transfer RNA–mediated editing in threonyl-tRNA synthetase: the class II solution to the double discrimination problem." Cell 103.6 (2000): 877-884. Dock-Bregeon, A. C., Rees, B., Torres-Larios, A., Bey, G., Caillet, J., & Moras, D. (2004). Achieving error-free translation: the mechanism of proofreading of threonyl-tRNA synthetase at atomic resolution. Molecular cell, 16(3), 375-386.