Enzymatic Synthesis of Sialyl Lactosamine Grafted Chitooligosaccharides

An efficient enzymatic assembly strategy was developed for the concise synthesis of structurally well-defined sialylated chitooligosaccharides. Two enzyme modules for the beta-1,3-N-acetyl-glucosaminylation and beta-1,4-galactosylation were applied for the grafting N-acetyl lactosamine (LacNAc) unit(s) onto the chitooligosaccharides. The LacNAc grafted chitooligosaccharides were further modified with alpha-2,3- or alpha-2,6-sialylation by two enzymatic sialylation modules to generate a total of 20 sialylated chitooligosaccharides. The inhibition study of influenza virus-induced cytopathy with synthetic sialylated chitooligosaccharides indicated that the sialic acid linkage and chain length both contribute to the binding preference and inhibition potency.