Table 3.

Amino acid groups adopted in this study

Group no.	Amino acids	Occurrence (%)1
1	Ala, Gly, Val	22.0
2	Ile, Leu, Phe, Pro	24.2
3	Tyr, Met, Thr, Ser	17.3
4	His, Asn, Gln, Tpr	11.4
5	Arg, Lys	11.4
6	Asp, Glu	12.2
7	Cys	1.4

This table follows the Shen et al.'s work [33]. ¹Occurrences of seven amino acid groups in the Swiss-Prot database release 57.0 [49].