TABLE 1 

Cellular lipid A composition after 90 min of environmental shift

Growth conditionMra[M-H]pb (m/z)No. of groups at 1 and/or 4′ positionNo. of acyl chain additions
Pcdi-PdP-pEtNeP-l-Ara4NfC16:0gOHh
7.6H to 7.6H1,7181,7151
1,7981,7752
1,7981,7962
1,8131,81121
1,8781,87611
7.6H to 5.8L1,7981,7752
1,7981,7962
1,8131,81121
1,8411,8381
1,8561,85411
1,9211,91811
1,9291,92611
2,0362,03321
2,0532,04911
2,0682,065111
5.8L to 5.8L1,7181,7161
1,7341,73211
1,7981,7512
1,7981,7672
1,7981,7962
1,8501,8471
1,8651,86311
1,8781,88211
1,8941,898111
1,9571,9541
2,0882,08611
2,1032,101111
2,1172,120111
2,1332,1361111
2,1602,161111
2,1752,1801111
2,2832,28721
2,2982,303211
  • a The Mr is the calculated molecular weight of the proposed structure; italicized values indicate less certainty in assignments.

  • b p is the predicted value for singly charged MS ions.

  • c P, unsubstituted monophosphate.

  • d di-P, unsubstituted diphosphate; at the 1 position.

  • e P-pEtN, diphosphoethanolamine; at either the 1 or the 4′ position but likely at the 1 position when l-Ara4N is present.

  • f P-l-Ara4N, phospho-l-Ara4N.

  • g C16:0, palmitate addition mediated by pagP.

  • h OH, in 2-hydroxymyristate mediated by lpxO.