Figure 1.

Analysis of the minimal acceptor length and product profiles of CsaB and CsxA. A, priming oligosaccharides of defined DP (DP2–DP7) were isolated using AEC. B, chemical structures of CPSX and CPSA. C and D, Alcian blue/silver-stained PAGEs illustrating synthesis products of CsaB (C) and CsxA (D) reactions in the presence (DP2–DP7) and absence (control) of priming oligosaccharides. An oligosaccharide mix (marker, DP10–DP60, avDP15) allows an estimate of the size of the generated CPS. E, CsaB reactions performed overnight in the presence of 2 mm donor substrate and varying concentrations of primCPSA demonstrated that the chains produced by CsaB depend on the d/a ratio. F, products of CsxA assembled at varying d/a ratios were non-uniform. primCPSX loaded onto the gel at the highest concentration used in the assay were not visible (the black square marks the position), affirming that all visible products were generated by the enzyme.