Page 126 - The Biochemistry of Inorganic Polyphosphates

WU095/Kulaev
WU095-07
Functions of polyphosphate and polyphosphate-dependent enzymes
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Figure 7.5 Changes in (a) PolyP content, (b and c) PolyP-metabolizing enzymes activities, and (c)
biomass and production of chlortetracycline during growth of the low-producing strain of Strepto-
myces aureofaciens 2209 (Kulaev et al., 1976). (a) (1) total acid-insoluble PolyP; (2) PolyP extracted
with hot perchloric acid; (3) salt-soluble PolyP: (b) (1) polyphosphate kinase (centre scale); (2)
1,3-diphosphoglycerate-polyphosphate phosphotransferase (right-hand scale); (3) PolyP glucokinase
(left-hand scale): (c) (1) biomass; (2) chlortetracycline; (3) exopolyphosphatase with PolyP 290 ; (4)
pyrophosphatase; (5) tripolyphosphatase.

in cells that overproduced exopolyphosphatase. When exopolyphosphatase-overproducing
cells were transformed again by a multicopy plasmid that carried the polyphosphate ki-
nase gene (ppk), the cells accumulated a great amount of PolyP and restored the UV and
mitomycin C sensitivities to the level of the control cells. In addition, a strain containing
multiple copies of ppk accumulated a large amount of PolyP. It is probable that PolyP is
necessary to regulate the expression of SOS genes (Shiba et al., 1997, 2000; Tsutsumi
et al., 2000).
The important role of polyphosphate kinase in the survival of E. coli under stress and
starvation was established by the study of a mutant deficient in the ppk1 gene and lacking
the most part of PolyP (Rao and Kornberg, 1996; Rao et al., 1998). Mutant cells show no