Automated glycan assembly of Streptococcus pneumoniae type 14 capsular polysaccharide fragments. Issue 40 (22nd June 2020)

• Record Type: Journal Article
• Authors: Louçano, João; Both, Peter; Marchesi, Andrea; Bino, Linda del; Adamo, Roberto; Flitsch, Sabine; Salwiczek, Mario
• Is Part Of: RSC advances. Volume 10:Issue 40(2020)
• Page Start: 23668
• Page End: 23674
• Publication Date: 2020-06-22
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra01803a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A streamlined automated synthesis for S. pneumoniae type 14 and Group B Streptococcus type III capsular oligosaccharides with only one set of three building blocks is presented. Competitive ELISA provides some insight into minimal epitope. Abstract : S. pneumoniae is a major human pathogen with increasing antibiotic resistance. Pneumococcal vaccines consist of capsular polysaccharide (CPS) or their related fragments conjugated to a carrier protein. The repeating unit of S. pneumoniae type 14 CPS shares a core structure with the CPS of Group B Streptococcus (GBS) type III: the only difference is that the latter exhibits a sialic acid unit, with a α-2, 3 linkage to galactose. Here, the automated glycan assembly (AGA) of two frameshifts of the repeating unit of S. pneumoniae type 14 is described. The same strategy is used to assemble dimers of the different repeating unit frameshifts. The four structures are assembled with only three commercially available monosaccharide building blocks. We also report an example of how enzymatic sialylation of the compounds obtained with AGA completes a synthetic route for GBS type III glycans. The synthesized structures were tested in competitive ELISA and further confirmed the branched tetrasaccharide Gal-Glc-(Gal-)GlcNAc to be the minimal epitope of S. pneumoniae type 14.