Introduction Elucidating how cold-active enzymes maintain efficient catalysis under low-temperature conditions remains a significant question in enzymology. Although enhanced conformational flexibility has been frequently associated with cold adaptation, flexibility alone cannot fully explain how catalytic precision and reproducibility are maintained. This suggests that an additional layer of structural organization is required. Methods In this study, a psychrophilic β-glucosidase (pBGL) from Pseudoalteromonas sp. BSw20308 and its mutant variant pBGL-S306P were examined through biochemical assays, molecular dynamics simulations, and dynamic interaction network analysis. Results The results indicate that pBGL preserves high catalytic efficiency at low temperature despite pronounced thermal instability, maintaining a rigid and conserved catalytic core. Notably, increased flexibility is spatially redistributed toward peripheral and interfacial regions rather than being globally amplified. Network analysis reveals that cold adaptation is associated with a distributed interaction network that connects these flexible regions to the catalytic core, constraining motions into coordinated dynamics that support catalysis. Discussion These findings suggest that cold adaptation in pBGL may involve not only enhanced flexibility but also network-mediated organization of conformational dynamics, providing a structural framework for understanding the activity–stability balance of cold-active enzymes.
Xian He, Mengting Liu, Xintong Li et al.· Frontiers in Microbiology· 1 citation
Polyethylene terephthalate (PET) is one of the most widely used synthetic plastics and a major contributor to global plastic pollution because of its high resistance to degradation. Enzymatic degradation by PET hydrolases (PETase) has emerged as a sustainable strategy for PET recycling; however, the limited thermostability of wild-type PETase restricts its industrial application. To elucidate the molecular basis underlying the different thermal behaviors of PET hydrolases, long-timescale molecular dynamics simulations were performed on WT-PETase, FAST-PETase, and the thermostable cutinase variant LCC-ICCG at 30 °C, 50 °C, and 70 °C. Comparative analyses integrating structural stability, residue flexibility, rigidity networks, free energy landscapes, and neural relational inference models revealed that FAST-PETase and LCC-ICCG exhibited enhanced conformational stability and reduced structural flexibility compared with WT-PETase, particularly under elevated temperatures. The improved thermostability was associated with more compact free energy landscapes, strengthened residue interaction networks, and better preservation of the catalytic architecture during thermal perturbation. These results suggest that an optimal balance between structural rigidity and conformational flexibility is critical for maintaining enzyme stability at elevated temperatures. Overall, this study provides molecular-level insights into the structural determinants of PETase thermostability and offers a theoretical framework for the rational engineering of efficient and heat-resistant plastic-degrading enzymes.
Hui Duan, Chen Wan, Bu-Qing Wang et al.· International Journal of Mol...· 0 citations