Temperature-dependent structural changes in xylanase II from Trichoderma longibrachiatum.
Nam, K.H.(2024) Carbohydr Res 541: 109173-109173
- PubMed: 38833820 
- DOI: https://doi.org/10.1016/j.carres.2024.109173
- Primary Citation of Related Structures:  
8YJI, 8YJJ - PubMed Abstract: 
Endo-β-1,4-xylanases degrade heteroxylans that constitute the lignocellulosic plant cell wall. This enzyme is widely used in the food, paper, textile, and biorefinery industries. Temperature affects the optimum activity of xylanase and is an important factor in its application. Various structural analyses of xylanase have been performed, but its structural influence by temperature is not fully elucidated. To better understand the structural influence of xylanase due to temperature, the crystal structure of xylanase II from Trichoderma longibrachiatum (TloXynII) at room and cryogenic temperatures was determined at 2.1 and 1.9 Å resolution, respectively. The room-temperature structure of TloXynII (TloXynII RT ) showed a B-factor value 2.09 times higher than that of the cryogenic-temperature structure of TloXynII (TloXynII Cryo ). Subtle movement of the catalytic and substrate binding residues was observed between TloXynII RT and TloXynII Cryo . In TloXynII RT , the thumb domain exhibited high flexibility, whereas in TloXynII Cryo , the finger domain exhibited high flexibility. The substrate binding cleft of TloXynII RT was narrower than that of TloXynII Cryo , indicating a distinct finger domain conformation. Numerous water molecule networks were observed in the substrate binding cleft of TloXynII Cryo , whereas only a few water molecules were observed in TloXynII RT . These structural analyses expand our understanding of the temperature-dependent conformational changes in xylanase.
Organizational Affiliation: 
College of General Education, Kookmin University, Seoul, 02707, Republic of Korea. Electronic address: structure@kookmin.ac.kr.