Fig. 1

a 3D model of MtCel6A; where α-helix, β-sheets and loops are highlighted in purple, blue and green, respectively. b 3D structure showing tunnel shape catalytic site. c Multiple sequence alignment of MtCel6A showing conserved critical amino acid residues; Asp 128 (catalytic acid) and Asp 314 (catalytic base) are marked with arrows, and other key residues (described in text) are marked with yellow diamond, triangle, and star