Class II Catalytic domain

The catalytic domain of the Class II aminoacyl-tRNA synthetase (AARS-II) activates amino acids so that their cognate tRNA can be charged. In total, thirteen of the 22 proteinogenic amino acids are incorporated into the protein, through at least 22 distinct AARS-II families; a single representative from each of which is displayed below. These amino acids are alanine, asparagine, aspartate, cysteine, glycine, histidine, lysine, phenylalanine, proline, pyrrolysine, selenocysteine, serine, and threonine. Lysine and cysteine are also incorporated during translation via the Class I aminoacyl tRNA synthetases [LysRS-I](/class1/lys) and [CysRS](/class1/cys). While still part part of the Class II catalytic domain superfamily, the $\beta$ subunits of the [PheRS](/class2/phe1) families do not in fact catalyze amino acid activation (Klipcan et al. 2020), but they are still displayed below.

References

Wang, Sheng, Jian Peng, and Jinbo Xu. "Alignment of distantly related protein structures: algorithm, bound and implications to homology modeling." Bioinformatics 27.18 (2011): 2537-2545. Gomez, Miguel Angel Rubio, and Michael Ibba. "Aminoacyl-tRNA synthetases." Rna 26.8 (2020): 910-936. Klipcan, Liron, et al. "Structural aspects of phenylalanylation and quality control in three major forms of phenylalanyl-tRNA synthetase." Journal of amino acids 2010 (2010). Kaiser, Florian, et al. "Backbone brackets and arginine tweezers delineate class I and class II aminoacyl tRNA synthetases." PLoS computational biology 14.4 (2018): e1006101.