TABLE 2.
MALDI-TOF mass spectrometry of hydrofluoric acid-released SCWPs from B. anthracis Sterne 34F2 (wild type) and isogenic ΔgtsE and ΔgtsE/pspac-gtsE variantsa
| Proposed composition of SCWPb | Observed m/z in: |
Theoretical m/z (monoisotopic) | ||
|---|---|---|---|---|
| Sterne | ΔgtsE strain | ΔgtsE/pspac-gtsE strain | ||
| HexNAc4-Gal2Na+ | 1,176.26 | 1,177.453 | ||
| HexNAc3-GlcN-Gal4Na+ | 1,458.41 | 1,459.52 | ||
| HexNAc5-GlcN-Gal32Na+ | 1,726.10 | 1,725.86 | ||
| HexNAc6-Gal32Na+ | 1,768.15 | 1,768.99 | ||
| HexNAc6-Gal4Na+ | 1,909.75 | 1,908.13 | ||
| HexNAc6-GlcN-Gal42Na+ | 2,091.76 | 2,092.11 | ||
| HexNAc6-Gal6Na+ | 2,232.65 | 2,233.64 | 2,231.79 | |
| HexNAc9-Gal6Na+ | 2,843.1 | 2,842 | ||
| HexNAc9-Gal9Na+ | 3,329.62 | 3,330.58 | 3,327.18 | |
a
Ion signals and proposed compositions of compounds from MALDI-TOF mass spectra of RP-HPLC-purified SCWPs from B. anthracis Sterne 34F2 and its ΔgtsE mutant and complemented variant ΔgtsE/pspac-gtsE.
b
The SCWPs isolated from wild-type Sterne and complemented ΔgtsE/pspac-gtsE strains generated nearly identical sets of ions, similar to the spectra characterizing the SCWP structure. Additional compositional explanations for the observed masses exist but are not listed here. HexNAc, ManNAc (N-acetylmannosaminyl) and GlcNAc (N-acetylglucosaminyl); GlcN, glucosaminyl; Gal, galactosyl.