Multiomics Identification and Structural Dynamics of PeXyn1: A Novel GH11 Xylanase from Pleurotus eryngii for Substrate Utilization.
The widely cultivated mushroom Pleurotus eryngii utilizes lignocellulosic biomass as a growth substrate, yet its xylanases remain poorly understood. Here, we identified PeXyn1, a novel cellulose-upregulated GH11 xylanase featuring a C-terminal carbohydrate-binding module (CBM1) domain, using integrated multiomics. Recombinant PeXyn1 exhibited an optimal pH of 4.5 and temperature of 50 °C, with remarkable stability across pH 4.5-7.5. Kinetic characterization yielded a Km of 27.51 mg mL-1 and a kcat of 20.95 s-1. Purified PeXyn1 efficiently saccharified corncob, releasing 4.258 mg mL-1 reducing sugars after 2 h. Notably, CBM1 truncation increased specific activity from 10.04 ± 0.29 to 28.79 ± 2.23 U mg-1, confirming the core's hydrolytic function while CBM1 mediates substrate anchoring. Simulations revealed an induced-fit mechanism with a high xylohexaose binding affinity (-11.7 kJ mol-1). Multivalent interactions at the CBM1-catalytic interface restrict structural fluctuations, promoting a stable conformation. This work offers the first molecular insight into P. eryngii xylanases, highlighting PeXyn1 for agro-waste valorization.