Laboratory of Applied Microbiology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Fushimi Pharmaceutical Co. Ltd., Marugame, Kagawa 763-8605, Japan.
J Biosci Bioeng. 2022 Jul;134(1):7-13. doi: 10.1016/j.jbiosc.2022.03.011. Epub 2022 Apr 25.
Endo-β-N-acetylglucosaminidases (ENGases) are enzymes that hydrolyze the N-linked oligosaccharides. Many ENGases have already been identified and characterized. However, there are still a few enzymes that have hydrolytic activity toward multibranched complex-type N-glycans on glycoproteins. In this study, one novel ENGase from Bacteroides nordii (Endo-BN) species was identified and characterized. The recombinant protein was prepared and expressed in Escherichia coli cells. This Endo-BN exhibited optimum hydrolytic activity at pH 4.0. High performance liquid chromatography (HPLC) analysis showed that Endo-BN preferred core-fucosylated complex-type N-glycans, with galactose or α2,6-linked sialic acid residues at their non-reducing ends. The hydrolytic activities of Endo-BN were also tested on different glycoproteins from high-mannose type to complex-type oligosaccharides. The reaction with human transferrin, fetuin, and α1-acid glycoprotein subsequently showed that Endo-BN is capable of releasing multi-branched complex-type N-glycans from these glycoproteins.
内-β-N-乙酰氨基葡萄糖苷酶（ENGases）是水解 N-连接寡糖的酶。已经鉴定和表征了许多 ENGases。然而，仍有一些酶对糖蛋白上的多分支复杂型 N-聚糖具有水解活性。在这项研究中，从拟杆菌 nordii（Endo-BN）种中鉴定和表征了一种新型的 ENGase。重组蛋白在大肠杆菌细胞中进行了制备和表达。该 Endo-BN 在 pH 4.0 时表现出最佳的水解活性。高效液相色谱（HPLC）分析表明，Endo-BN 优先水解核心岩藻糖基化的复杂型 N-聚糖，其非还原末端具有半乳糖或α2,6-连接的唾液酸残基。还测试了 Endo-BN 在不同糖蛋白上的水解活性，从高甘露糖型到复杂型寡糖。与人转铁蛋白、胎球蛋白和α1-酸性糖蛋白的反应表明，Endo-BN 能够从这些糖蛋白中释放出多分支的复杂型 N-聚糖。
