Computer-Aided Engineering of a Transglycosylase for the Glucosylation of an Unnatural Disaccharide of Relevance for Bacterial Antigen Synthesis

摘要: The exploration of chemo-enzymatic routes to complex carbohydrates has been hampered by the lack appropriate enzymatic tools having substrate specificity for new reactions. Here, we used a computer-aided design framework guide construction small, diversity-controlled library amino acid sequences an α-transglucosylase, sugar binding subsites which were re-engineered enable challenging 1,2-cis-glucosylation partially protected β-linked disaccharide allyl (2-deoxy-2-trichloroacetamido-β-d-glucopyranosyl)-(1→2)-α-l-rhamnopyranoside, potential intermediate in synthesis Shigella flexneri cell-surface oligosaccharides. target is not recognized parental wild-type enzyme and exhibits molecular structure very distinct from that natural α-(1→4)-linked acceptor. A profound reshaping pocket had thus be performed. Following selection 23 positions first shell, mutations sampled using Ro...