The contribution of specific subsites to catalytic activities in active site architecture of a GH11 xylanase.

• Xylanase of GH11 family is a good industrial candidate. • The roles of residues at each subsite of GH11 xylanase active site are explored. • The two aromatic residues at the + 2 and + 3 subsites are necessary for the catalysis. • Y180W and Y96W increased the enzymatic activity by 6.2% and 12.8% at low temperature.