TABLE 1.

Negative-ion CE-ES-MS data and compositions of O-deacylated LPS and fully deacylated LPS (KOH treated) for A. baumannii 307-0294 and 307::TN17

StrainObserved ions (m/z)aObserved molecular ion (m/z)Calculated molecular ion (m/z)Proposed composition
(M-H)(M-2H)2−(M-3H)3−
O-deacylated LPS
    A. baumannii 307-02941400.5933.52803.32800.7Lipid A-OH, 3 Kdo, 2 HexN, HexNAcA, 4 Hexb
    307::TN171391.01392.01392.36Lipid A-OH, 2 Kdo
1172.01173.01172.18Lipid A-OH, Kdo
952.5953.5952.0Lipid A-OH
Fully deacylated LPS
    A. baumannii 307-02941153.0768.12307.72307.03 Kdo, 2 HexN, HexNA, 4 Hex, 2 HexN, 2 P, H2O
    307::TN17939.3469.2940.4940.62 Kdo, 2 HexN, 2 P, H2O
719.1720.1720.5Kdo, 2 HexN, 2 P, H2O
499.02 HexN, 2 P, H2O
  • a Average mass units (in daltons) were used for calculation of molecular masses based on the proposed composition, as follows: Lipid A-OH, 952.00; Hex, 162.15; Kdo, 220.18; HexN, 161.19; HexNAc, 203.19; HexNAcA, 218.19; and P, 79.95.

  • b Lipid A-OH contains two N-acylated glucosamine residues, two phosphate residues, and a water molecule.