An expeditious and efficient synthesis of β-d-galactopyranosyl-(1→3)-d-N-acetylglucosamine (lacto-N-biose) using a glycosynthase from Thermus thermophilus as a catalyst
作者:Ayité D’Almeida、Marina Ionata、Vinh Tran、Charles Tellier、Michel Dion、Claude Rabiller
DOI:10.1016/j.tetasy.2009.05.007
日期:2009.6
Mutant glycosynthases or transglycosidases obtained from a Thermus thermophilus β-d-glycosidase (TtbGly) efficiently catalyzed the synthesis of β-(1→3)-disaccharides. Unfortunately, this regioselectivity was changed to the β-(1→4) one when N-acetylglucosamine derivatives were used as acceptors, thus precluding the possibility of synthesizing d-Galp-β-(1→3)-d-GlcpNAc (lacto-N-biose) or d-Glcp-β-(1→3)-d-GlcpNAc
从嗜热栖热菌β-d-糖苷酶(TtbGly)获得的突变糖合酶或转糖苷酶有效地催化了β-(1→3)-二糖的合成。不幸的是,当使用N-乙酰基葡糖胺衍生物作为受体时,该区域选择性变成了β-(1→4),因此排除了合成d-Gal p - β-(1→3)-d-Glc p NAc的可能性。(乳糖-N-二糖)或d-Glc p - β-(1→3)-d-Glc pNAc,是合成抗原决定簇的有用合成子。相反,我们在这项工作中表明,在存在苯基2-氨基-1-硫代-β-d-吡喃葡萄糖苷的情况下,发生了E338G TtbGly糖合酶的“正常”β-(1→3)区域选择性。因此,使用α-半乳糖基或α-葡萄糖基氟化物进行转糖基化反应可得到高收率的相应苯基β-d-glycopyranosyl-(1→3)-2-氨基-2-脱氧-1-硫代-β-d-葡萄糖基吡喃糖苷(88 –97%)。随后的选择性N-酰化,然后对苯硫醚进行NBS /水脱保