Comparison of the proton NMR spectra anomeric regions and repeating unit structures of HF-SCWPs from representative B. anthracis and related B. cereus strains.

(A)B. anthracis Sterne 34F2; (B) the close phylogenetically related human infection-associated B. cereus strain G9241; (C) a great ape isolate, B. cereus strain CA (Cameroon). All SCWPs share a conserved HexNAc backbone; the Ba strains lack Gal substituents on the backbone ManNAc residue, while the examined human infection-associated Bc strains (G9241 and 03BB87) exhibit a Gal monosaccharide substitution (residue G) on a percentage of their ManNAc [27]. The great ape Bc isolates exhibit variable degrees of Gal monosaccharide and Gal disaccharide substitutions (residues G, J, and K) at ManNAc, which results in additional ManNAc signal heterogeneity (B, B′, and B′′). The repeating unit structures of the Ba and human infection–associated Bc HF-SCWPs (panels A and B), including glycosidic sequence and linkage positions, were deduced from 1H-13C HMBC, 1H-1H-NOESY, and chemical linkage analysis, previously published [12,26,27].