The Multiple Roles of Polyphosphate in <b><i>Ralstonia eutropha</i></b> and Other Bacteria

Abstract

An astonishing variety of functions has been attributed to polyphosphate (polyP) in prokaryotes. Besides being a reservoir of phosphorus, functions in exopolysaccharide formation, motility, virulence and in surviving various forms of stresses such as exposure to heat, extreme pH, oxidative agents, high osmolarity, heavy metals and others have been ascribed to polyP. In this contribution, we will provide a historical overview on polyP, will then describe the key proteins of polyP synthesis, the polyP kinases, before we will critically assess of the underlying data on the multiple functions of polyP and provide evidence that – with the exception of a P-storage-function – most other functions of polyP are not relevant for survival of &lt;i&gt;Ralstonia eutropha&lt;/i&gt;, a biotechnologically important beta-proteobacterial species.

Polyphosphate Kinase 2 (PPK2) Enzymes: Structure, Function, and Roles in Bacterial Physiology and Virulence

“…To study the contribution of these enzymes to R. eutropha physiology, Rosigkeit et al tested the effects of various stressors on the ∆ ppk-all strain. Surprisingly, the ∆ ppk-all mutant showed no defects in heat shock survival, oxidative stress survival, or motility—all phenotypes that have previously been linked to PPK1 in E. coli [ 19 , 33 , 58 ]. The ∆ ppk-all mutant did display a marginal growth defect in phosphate-depleted media, indicating a role of polyP and PPK1/2s in R. eutropha phosphate storage [ 58 ].…”

“…Surprisingly, the ∆ ppk-all mutant showed no defects in heat shock survival, oxidative stress survival, or motility—all phenotypes that have previously been linked to PPK1 in E. coli [ 19 , 33 , 58 ]. The ∆ ppk-all mutant did display a marginal growth defect in phosphate-depleted media, indicating a role of polyP and PPK1/2s in R. eutropha phosphate storage [ 58 ]. Given the remarkable number of PPK2 enzymes in R. eutropha , it seems likely that additional roles for these enzymes remain to be discovered.…”

Synthetic metabolism for in vitro acetone biosynthesis driven by ATP regeneration

“…Both reactions use polyP as a phosphate donor (Fig. 3), a class of polymeric phosphate salt (widespread in nature [59][60][61] ) that has been flagged as a nearly ideal substrate for ATP regeneration due to its low cost and stability in aqueous solutions. 62 In a first step, an assay was carried out to assess the potential of the designed ATP REG system to increase the production of acetone with a limited starting amount of ATP.…”

Stress Resistance of Saccharomyces cerevisiae Strains Overexpressing Yeast Polyphosphatases

“…Inorganic polyphosphate (polyP), a linear polymer containing a few to several hundred orthophosphate residues, participates in various processes regulating vital activities [1][2][3][4], including stress response in microbial cells [1,[5][6][7][8][9]. PolyP and polyphosphate kinases are involved in the induction of the synthesis of RpoS, an RNA polymerase subunit in bacteria that provides the expression of the genes responsible for adaptation to the stationary stage and are necessary for bacterial cell motility, biofilm formation, and virulence [1].…”