Abstract Lytic polysaccharide monooxygenase (LPMO), a kind of copper-dependent oxidases, has been widely used for the efficient enzymatic hydrolysis of lignocellulosic biomass. In this study, a gene encoding the LPMO from Myceliophthora thermophila C1 (MtC1LPMO) was expressed in Pichia pastoris GS115. A high secretion level of recombinant MtC1LPMO protein was obtained in the culture medium using its native signal peptide. Consequently, MtC1LPMO with a purity of more than 95 % and yield of 46 mg/L was obtained. The optimal enzyme activity was observed at pH 7.5 and 85 °C, and the enzyme displayed remarkable thermostability at 40–60 °C. MtC1LPMO exhibited a synergistic activity with cellulase in the degradation of microcrystalline cellulose, and the reducing sugar content increased by 29 % compared to cellulase alone. Additionally, the results of scanning electron microscopy revealed that MtC1LPMO would cleave the glycosidic chain, leading to subsequent disruption to the surface of microcrystalline cellulose. Finally, the interaction model of MtC1LPMO and cellohexaose was explored using molecular docking simulations, which showed that the residues H1, H68, Y153, H142, Y67, V143, S146, G149, Q151 and P69 of MtC1LPMO played an important role in interacting with cellohexaose.

中文翻译：

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嗜热毁丝霉C1裂解多糖单加氧酶及其在纤维素糖苷链裂解中的表征

摘要 裂解多糖单加氧酶（LPMO）是一种铜依赖性氧化酶，已广泛用于木质纤维素生物质的高效酶水解。在这项研究中，编码来自嗜热毁丝霉 C1 (MtC1LPMO) 的 LPMO 的基因在毕赤酵母 GS115 中表达。使用其天然信号肽在培养基中获得了高分泌水平的重组 MtC1LPMO 蛋白。因此，获得了纯度超过 95% 和产率 46 mg/L 的 MtClLPMO。在 pH 7.5 和 85°C 下观察到最佳酶活性，并且酶在 40-60°C 显示出显着的热稳定性。MtC1LPMO在微晶纤维素的降解中表现出与纤维素酶的协同活性，还原糖含量比单独使用纤维素酶提高了29%。此外，扫描电子显微镜的结果显示 MtC1LPMO 会裂解糖苷链，导致随后对微晶纤维素表面的破坏。最后，通过分子对接模拟探索了 MtC1LPMO 与纤维六糖的相互作用模型，结果表明 MtC1LPMO 的残基 H1、H68、Y153、H142、Y67、V143、S146、G149、Q151 和 P69 在与纤维六糖的相互作用中起重要作用.