Mutant deletions in Escherichia coli affect the cellular levels of undecaprenyl phosphate and undecaprenyl diphosphate

抄録

Escherichia coli multiple-deletion mutants were constructed to examine the lipid phosphatase genes. Ratio of cellular levels of undecaprenyl phosphate (UP) and undecaprenyl diphosphate (UPP) was determined using cells labeled with 14C and measuring the radioactivities in these lipids. The labeled cells were obtained through feeding [14C]isopentenyl diphosphate to an E. coli strain. The relative level of UP in the wild type strain W3110; in the YS1234 strain defective in ynbD, yeiU, ybjG, and pgpB; in the YS1235 strain defective in ynbD, yeiU, ybjG, and bacA; and in the YS1245 strain defective in ynbD, yeiU, pgpB, and bacA were 78.0% ± 3.5%, 74.7% ± 1.2%, 68.4% ± 6.8%, and 64.0% ± 7.5%, respectively. The quadruple mutant strain that possessed the wild-type bacA showed almost identical UP level as the wild type strain W3110, indicating that sufficient level of UPP phosphatse activity was conferred by a bacA product without the products of ynbD, yeiU, ybjG, and pgpB. However, the mutants defective in bacA showed a slight but significant (p 0.01) decrease in the UP level.