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The effect of polyphosphate kinase gene deletion on polyhydroxyalkanoate accumulation and carbon metabolism in P seudomonas putida KT 2440
Author(s) -
Casey William T.,
NikodinovicRunic Jasmina,
Fonseca Garcia Pilar,
Guzik Maciej W.,
McGrath John W.,
Quinn John P.,
Cagney Gerard,
Prieto Maria Auxiliadora,
O'Connor Kevin E.
Publication year - 2013
Publication title -
environmental microbiology reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.229
H-Index - 69
ISSN - 1758-2229
DOI - 10.1111/1758-2229.12076
Subject(s) - glycerol kinase , biochemistry , wild type , mutant , pep group translocation , pyruvate kinase , biology , kinase , microbiology and biotechnology , chemistry , glycerol , metabolism , glycolysis , gene
Summary The primary enzyme involved in polyphosphate (poly P ) synthesis, poly P kinase ( ppk ), has been deleted in P seudomonas putida KT 2440. This has resulted in a threefold to sixfold reduction in polyhydroxyalkanoate ( PHA ) accumulation compared with the wild type under conditions of nitrogen limitation, with either temperature or oxidative ( H 2 O 2 ) stress, when grown on glucose. The accumulation of PHA by Δppk mutant was the same as the wild type under nitrogen‐limiting growth conditions. There was no difference in poly P levels between wild‐type and Δppk strains under all growth conditions tested. In the Δppk mutant proteome, poly P kinase ( PPK ) was undetectable, but up‐regulation of the polyp‐associated proteins poly P adenosine triphosphate ( ATP )/nicotinamide adenine dinucleotide ( NAD ) kinase ( PpnK ), a putative poly P adenosine monophosphate ( AMP ) phosphotransferase ( PP _1752), and exopolyphosphatase was observed. Δ ppk strain exhibited significantly retarded growth with glycerol as carbon and energy source (42 h of lag period compared with 24 h in wild‐type strain) but similar growth to the wild‐type strain with glucose. Analysis of gene transcription revealed downregulation of glycerol kinase and the glycerol facilitator respectively. Glycerol kinase protein expression was also downregulated in the Δ ppk mutant. The deletion of ppk did not affect motility but reduced biofilm formation. Thus, the knockout of the ppk gene has resulted in a number of phenotypic changes to the mutant without affecting poly P accumulation.