ISSN:
1617-4623
Keywords:
Key words Chemotaxis
;
pho regulon
;
Phosphate
;
Phosphate transport
;
Pseudomonas aeruginosa
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The organization of the phosphate-specific transport (pst) operon in Pseudomonas aeruginosa has been determined. The gene order of the pst operon is pstC, pstA, pstB, phoU, and a well-conserved Pho box sequence (16/18 bases identical) exists in the promoter region. The most striking difference from the known Escherichia coli pst operon is the lack of the pstS gene encoding a periplasmic phosphate (Pi)-binding protein. Even though the three pst genes were absolutely required for Pi-specific transport, expression of the pst operon at high levels did not increase Pi uptake in P. aeruginosa. DNA sequences for the pstB and phoU genes have been determined previously. The newly identified pstC and pstA genes encode possible integral membrane proteins of 677 amino acids (M r 73 844) and 513 amino acids (M r 56 394), respectively. The amino acid sequences of PstC and PstA predict that these proteins contain a long hydrophilic domain not seen in their E. coli counterparts. A chromosomal deletion of the entire pst operon rendered P. aeruginosa unable to repress Pi taxis under conditions of Pi excess. The phoU and pstB genes are essential for repressing Pi taxis. However, mutants lacking either PstC or PstA alone were able to repress Pi taxis under conditions of Pi excess.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02172980
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