TABLE 2.

Levels of polyamines in CAG2242/pUCmdtJI and its mutants cultured with 2 mM spermidinea

StrainPolyamine concn (mM)
PutrescineSpermidine
CAG2242/pUCmdtJI0.49 ± 0.1211.7 ± 0.42
mdtJ(Y4L)0.14 ± 0.0536.0 ± 1.39
mdtJ(W5L)0.23 ± 0.0724.1 ± 0.99
mdtJ(E15Q)0.07 ± 0.0324.7 ± 1.83
mdtJ(Y45L)0.33 ± 0.1431.1 ± 0.64
mdtJ(Y61L)0.36 ± 0.0933.0 ± 1.56
mdtJ(E82Q)0.19 ± 0.1131.9 ± 2.01
mdtI(E5Q)0.36 ± 0.1830.9 ± 2.30
mdtI(E19Q)0.60 ± 0.2423.2 ± 1.35
mdtI(D60N)0.65 ± 0.1520.9 ± 0.49
mdtI(W68L)0.24 ± 0.1029.4 ± 2.14
mdtI(W81L)0.18 ± 0.1320.7 ± 0.88
  • a E. coli CAG2242/pUCmdtJI and its mutants were cultured in the presence of 2 mM spermidine for 24 h, and the polyamine content in cells was measured as described in Materials and Methods. Values are means ± SD for three samples.