Table 2.

degP expression and hypersensitivity of OmpF mutants

OmpF340 residuea or vectorRelativedegPexpressionbGrowth inhibitionc by:
Rifampin (5 μg)Erythromycin (15 μg)
F340 (parent)1.009.508.50d
Y3401.60 ± 0.0610.758.75d
L3401.44 ± 0.0710.258.25d
P3401.29 ± 0.1016.5014.00
H3402.02 ± 0.1614.0010.50
T3401.31 ± 0.1511.258.75d
S3401.85 ± 0.1814.0011.00
R3401.89 ± 0.0615.0011.75
A3401.77 ± 0.0111.259.00d
  • a OmpF proteins were expressed from plasmids (without IPTG) in a genetic background lacking the chromosomal OmpF protein.

  • b degP expression was determined by utilizing a degP::lacZ+construct. β-Galactosidase assays were done in triplicate. Cells were grown in Luria broth with ampicillin. Similar data were obtained from exponential cultures and cultures grown overnight.

  • c Experiments to determine inhibition zones were carried out in triplicate. The diameter of presoaked antibiotic paper disks was 7 mm.

  • d Fuzzy inhibition zones.