Normalized amino acid count per protein. The number of amino acids was normalized with respect to protein length. Amino acid composition of (A) endoglucanases enzyme group, (B) endoglucanase retaining catalytic mechanism, (C) (α/β)8 fold, (D) β-jelly roll fold, and (E) (α/α)6 fold. The mean of each amino acid and its standard error are shown in each plot, grouped as reported in  into charged (DEKR), hydrophobic (ACFILMPVWY), and hydrophilic (HNQST) residues. Solid lines represent thermophilic protein set (squares show means) and dotted lines represent mesophilic protein set (diamonds show means). The statistically significant amino acids are shown in Figure 3. Note that the results for the (α/α)6 fold and the endoglucanase inverting mechanism are the same.