Structure modeling of the protein Cel12B. Different segments of the protein secondary structure are colored accordingly. The catalytic amino acids (Glu131 and Glu229) locating in the center of the structure were labeled in red (a, b, d). The amino acids Trp115, Trp135 and Trp175 were labeled in magenta (a, b, c), Met133 was labeled in blue (a, b), where these four amino acids show a great importance in the substrate binding. The amino acids Pro63 and Pro83 were labeled in black (a, c, d), Gly30 and Gly227 were labeled in cyan (a, b, d), where these four amino acids are well related to the thermostability of the enzyme.