Table 5.

Importance of conserved ‘identity positions’ in tRNAs from the three domains of life, as measured by relative Eentropy according to (385)

tRNA families	Nucleotides with important identity positions
Arg	4–69; 20; 36
Cys	3–70; 13–22; 34; 35; 36
Ile	29–41; 34; 35; 36
Leu	12–23; 35; 36
Met	31–39; 34; 35; 36
Val	35 ; 36; 73
Glu	11–24; 12–23; 13, 34; 35; 36
Gln	12–23; 13–22; 34; 35; 38; 44; 73
Trp	31–39; 34; 35; 36
Tyr	12–23; 34; 35; 36
Ala	2–71; 3–70; 4–69; 20a; 35; 36
Gly	2–71; 3–70; 31–39; 35; 36
His	2–71; 32; 34; 35; 36; 38
Pro	2–71; 35; 36; 37
Ser	13–22; 35; 36; 46; 47; 73
Thr	35 ; 36
Asp	11–24; 20a; 25; 31–39; 34; 35; 36; 73
Asn	2–71; 31–39; 34; 35; 36; 51–63; 73
Lys	12–23; 34; 35; 36
Phe	12–23; 20a; 34; 35; 36; 73

tRNA families refer to the ensemble of isoacceptors and isodecoders specific to a given proteinogenic amino acid. Data are displayed according to the ranking of aaRSs in two classes, each subdivided into three subclasses. Relative entropy (RE) values are shown in regular black (RE 0.22–0.4) and bold black (RE ∼0.4–0.7). Note that RE values >0.7 are found in a few tRNA families from specific domains of life (see Supplementary Tables S3–S5). Positions of anticodons are underlined. Positions in italics are occupied in some taxa by validated determinants for tRNA aminoacylation.