Isolation of a Tn501 insertion mutant lacking porin protein P of Pseudomonas aeruginosa.
In order to demonstrate a role for anion-specific protein P channels in phosphate transport in Pseudomonas aeruginosa PAO, we wished to isolate a transposon insertion mutant deficient in protein P. A number of transposon delivery systems were tested which yielded, for the most part, whole plasmid inserts. Plasmid pMT1000 (Tsuda et al. 1984), a temperature-sensitive R68 plasmid carrying the transposon Tn501, was successfully employed in the isolation of a Tn501 insertion mutant lacking protein P under normally inducing conditions. To identify the mutant deficient in protein P, a protein P-specific polyclonal antiserum was used. This mutant, strain H576, was deficient in high-affinity phosphate transport exhibiting a Km for uptake (3.60 +/- 0.64 microM) almost ten times greater than that of the wild type strain (Km = 0.39 microM). There was, however, no change in the Vmax for high-affinity phosphate transport as a result of the loss of protein P in this mutant. The protein P-deficiency of the mutant correlated with a growth defect in a phosphate-limited medium, resulting in an 18%-35% decrease in growth when compared with the wild type.
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D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D003227:Conjugation, Genetic; D003470:Culture Media; D004251:DNA Transposable Elements; D007473:Ion Channels / Q000378:metabolism*; D009154:Mutation; D010957:Plasmids; D018272:Porins; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development
D001425:Bacterial Outer Membrane Proteins; D003470:Culture Media; D004251:DNA Transposable Elements; D007473:Ion Channels; D018272:Porins