Figure 4
1D 1H NMR spectra of CPS preparations from serotypes 14 and 1 in 33 mM phosphate pD 8.0 in D2O. (a,b) Full spectrum. (c–f) Expansion of the methyl region. (a,d) SS14to1 mutant, 500 MHz, 75 °C. (b,f) SS1to14 mutant, 500 MHz, 77 °C. (c) Serotype 14 field strain, 500 MHz, 77 °C18. (e) Serotype 1 field strain, 700 MHz, 70 °C19. Specific characteristics of the 1H NMR spectrum due to the presence of GalNAc in the native serotype 1 CPS were also found in the spectrum of the CPS from the corresponding mutant expressing serotype 1 CPS. Conversely, the spectrum of the CPS from the mutant expressing serotype 14 CPS, as well as that of the native serotype 14 CPS, lacked the signal attributed to N-acetyl of GalNAc.
