A polyphosphate kinase 1 (ppk1) mutant of Pseudomonas aeruginosa exhibits multiple ultrastructural and functional defects

*Department of Biochemistry, Stanford University School of Medicine, 279 West Campus Drive, Stanford, CA 94305-5307;
^†Genencor International, Inc., 925 Page Mill Road, Palo Alto, CA 94304;
^‡ICOS Corporation, 22021 20th Avenue SE, Bothell, WA 98021;
^§Department of Pharmacy and Pharmacology, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom; and
^¶Research Institute of Healthcare Science, School of Applied Sciences, University of Wolverhampton, Wulfruna Street, Wolverhampton WV1 1SB, United Kingdom

Contributed by Arthur Kornberg, November 6, 2006 (received for review July 10, 2006)

Abstract

Pseudomonas aeruginosa, of medical, environmental, and industrial importance, depends on inorganic polyphosphate (poly P) for a wide range of functions, especially survival. Mutants of PAO1 lacking poly P kinase 1, PPK1, the enzyme responsible for most poly P synthesis in Escherichia coli and other bacteria, are defective in motility, quorum sensing, biofilm formation, and virulence. We describe here multiple defects in the ppk1 mutant PAOM5, including a striking compaction of the nucleoid, distortion of the cell envelope, lack of planktonic motility and exopolymer production, and susceptibility to the β-lactam antibiotic carbenicillin as well as desiccation. We propose that P. aeruginosa with reduced poly P levels undergoes ultrastructural changes that contribute to profound deficiencies in cellular functions.

Footnotes

^‖To whom correspondence should be addressed. E-mail: akornber{at}cmgm.stanford.edu
Author contributions: C.D.F., M.H.R., S.S.K.L., R.G., J.H., P.J.W., M.R.W.B., and A.K. designed research; C.D.F., M.H.R., S.S.K.L., R.G., J.H., P.J.W., and M.R.W.B. performed research; C.D.F., M.H.R., S.S.K.L., R.G., J.H., P.J.W., M.R.W.B., and A.K. analyzed data; and C.D.F. wrote the paper.
The authors declare no conflict of interest.
This article contains supporting information online at www.pnas.org/cgi/content/full/0609733104/DC1.
Abbreviations:

poly P,

polyphosphate;

PPK,

polyphosphate kinase;

PPX,

exopolyPase.
Freely available online through the PNAS open access option.