Fig. 1. Proposed reaction mechanism of inverting cellulase and the close-up views of catalytic site of PcCel45A.

(A) Reaction scheme of inverting cellulase. The general acid should be protonated and the general base should be deprotonated for the reaction. (B) Comparison of residues around the catalytic centers of HiCel45A (pink) and PcCel45A (green). (C) X-ray omit map of cellopentaose at subsites +1 to +5 of PcCel45A WT at room temperature (2σ level).