AbstractHerein, we describe the efficient gram‐scale synthesis of α2,3‐ and α2,6‐sialyllactose oligosaccharides as well as mimetics from N‐acyl mannosamines and lactose in metabolically engineered bacterial cells grown at high cell density. We designed new Escherichia coli strains co‐expressing sialic acid synthase and N‐acylneuraminate cytidylyltransferase from Campylobacter jejuni together with the α2,3‐sialyltransferase from Neisseria meningitidis or the α2,6‐sialyltransferase from Photobacterium sp. JT‐ISH‐224. Using their mannose transporter, these new strains actively internalized N‐acetylmannosamine (ManNAc) and its N‐propanoyl (N‐Prop), N‐butanoyl (N‐But) and N‐phenylacetyl (N‐PhAc) analogs and converted them into the corresponding sialylated oligosaccharides, with overall yields between 10 % and 39 % (200‐700 mg.L−1 of culture). The three α2,6‐sialyllactose analogs showed similar binding affinity for Sambucus nigra SNA−I lectin as for the natural oligosaccharide. They also proved to be stable competitive inhibitors of Vibrio cholerae neuraminidase. These N‐acyl sialosides therefore hold promise for the development of anti‐adhesion therapy against influenza viral infections.
摘要我们介绍了在高密度生长的代谢工程细菌细胞中高效合成α2,3-和α2,6-半乳糖低聚糖以及 N-酰甘露胺和乳糖的模拟物。我们设计了新的大肠杆菌菌株,共同表达空肠弯曲杆菌的硅铝酸合成酶和 N-酰基神经氨酸胞苷酸转移酶,以及脑膜炎奈瑟氏菌的α2,3-氨酰基转移酶或光杆菌 JT-ISH-224 的α2,6-氨酰基转移酶。这些新菌株利用其甘露糖转运体,积极内化 N-乙酰甘露糖胺(ManNAc)及其 N-丙酰基(N-Prop)、N-丁酰基(N-But)和 N-苯乙酰基(N-PhAc)类似物,并将其转化为相应的苷元化寡糖,总产率介于 10 % 和 39 % 之间(200-700 mg.L-1 培养物)。这三种 α2,6-半乳糖类似物与天然寡糖一样,对黑杨 SNA-I 凝集素具有相似的结合亲和力。它们还被证明是霍乱弧菌神经氨酸酶的稳定竞争性抑制剂。因此,这些 N-酰基半乳糖苷有望用于开发抗流感病毒感染的抗粘附疗法。