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Media type:
E-Article
Title:
Cloning and Characterization of Polyphosphate Kinase and Exopolyphosphatase Genes from Pseudomonas aeruginosa 8830
Contributor:
Zago, Anna;
Chugani, Sudha;
Chakrabarty, A. M.
Published:
American Society for Microbiology, 1999
Published in:
Applied and Environmental Microbiology, 65 (1999) 5, Seite 2065-2071
Language:
English
DOI:
10.1128/aem.65.5.2065-2071.1999
ISSN:
0099-2240;
1098-5336
Origination:
Footnote:
Description:
<jats:title>ABSTRACT</jats:title>
<jats:p>
<jats:italic>Pseudomonas aeruginosa</jats:italic>
accumulates polyphosphates in response to nutrient limitations. To elucidate the function of polyphosphate in this microorganism, we have investigated polyphosphate metabolism by isolating from
<jats:italic>P. aeruginosa</jats:italic>
8830 the genes encoding polyphosphate kinase (PPK) and exopolyphosphatase (PPX), which are involved in polyphosphate synthesis and degradation, respectively. The 690- and 506-amino-acid polypeptides encoded by the two genes have been expressed in
<jats:italic>Escherichia coli</jats:italic>
and purified, and their activities have been tested in vitro. Gene replacement was used to construct a PPK-negative strain of
<jats:italic>P. aeruginosa</jats:italic>
8830. Low residual PPK activity in the
<jats:italic>ppk</jats:italic>
mutant suggests a possible alternative pathway of polyphosphate synthesis in this microorganism. Primer extension analysis indicated that
<jats:italic>ppk</jats:italic>
is transcribed from a ς
<jats:sup>E</jats:sup>
-dependent promoter, which could be responsive to environmental stresses. However, no coregulation between
<jats:italic>ppk</jats:italic>
and
<jats:italic>ppx</jats:italic>
promoters has been demonstrated in response to osmotic shock or oxidative stress.
</jats:p>