TABLE 1 

MALDI-TOF MS profiles of lipid A species from E. coli MG1655 strains expressing eptA, mcr-1, mcr-2, and their point mutants

Protein,
lipid species
Mass (m/z) of lipid species from E. coli MG1655 bearing:
Empty
vector
No vector
(WTa)
Vector expressing protein with indicated mutation
EptAN106AT110AE114AE240AT280AS325AK328AH378AH383AD452AH453AH465A
    Lipid A1,796.7001,797.9361,797.021,797.0831,796.9501,797.0691,796.7191,797.1381,797.0051,796.8931,796.7341,796.9351,796.8141,796.869
    PPEA-4′-lipid A1,919.9831,920.0771,920.1411,920.195
MCR-1bN108AT112AE116AE246AT285AS330AK333AH390AH395AD465AH466AH478A
    Lipid A1,796.5671,796.9151,796.5721,796.7071,796.5981,796.6451,796.5211,796.6511,796.6761,796.7861,796.5351,796.6751,796.7181,796.912
    PPEA-4′-lipid A1,919.9691,919.6141,919.7531,919.695
MCR-2N106AT110AE114AE244AT283AS328AK331AH388AH393AD463AH464AH476A
    Lipid A1,796.2431,796.9391,796.9861,796.8121,796.6221,796.5711,796.7221,796.7171,796.5381,796.8601,796.0701,796.6111,796.6021,796.664
    PPEA-4′-lipid A1,919.9911,919.1141,919.8571,919.753
  • a WT, wild type.

  • b The mass data for MCR-1 are adapted from the recent description by our research group (44).