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| Format: | Artículo científico |
| Sprache: | en |
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Journal of agricultural and food chemistry
2025
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| Online-Zugang: | https://pubmed.ncbi.nlm.nih.gov/41178039/ |
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Inhaltsangabe:
- Catalytic Mechanism and Secondary-Structure-Type-Dependent Allosteric Regulation of β-Agarase Amaga. Wang, Xinyi Ye, Mianquan Chi, Zirong Yao, Ronghui Long, Hao Cai, Xiaoni Ren, Wei Xie, Zhenyu Allosteric Regulation Kinetics Glycoside Hydrolases Protein Structure, Secondary Fungal Proteins Biocatalysis Allosteric Site Molecular Docking Simulation Catalytic Domain Glycosylation It remains unclear whether enzymic allosteric sites on distinct secondary structure types mediate differential dynamic conformational transitions. Herein, we investigated the catalytic mechanism and secondary-structure-type-dependent allosteric regulation of β-agarase Amaga, specifically producing neoagaro-tetraose (NA4) and neoagaro-hexaose (NA6). Using homology modeling, molecular docking, point mutations, structural quantification, and kinetic analysis, we identified six key catalytic residues (Glu147, Asp149, Glu152, His169, His173, and Glu281) forming a retaining mechanism: Glu152, His169, Glu281, and Glu147 facilitate glycosylation, while Glu152 and His173 coordinate deglycosylation, with Asp149 maintaining the charge equilibrium. Notably, five β-sheet-localized residues of these six highlight their structural dominance. Allosteric site mutations revealed that random coil-localized sites enhance activity by converting random coils into α-helices, whereas β-sheet-localized sites drive transitions from β-sheets to α-helices, β-turns, and random coils. Despite differing pathways, higher-activity mutants exhibited faster structural transitions and increased NA4 production. These findings highlight secondary-structure-type-dependent design in engineering enzymes with tailored product specificity.