Inorganic Polyphosphate Is Required for Motility of Bacterial Pathogens

The ppk gene encodes polyphosphate kinase (PPK), the principal enzyme in many bacteria responsible for the synthesis of inorganic polyphosphate (polyP) from ATP. A null mutation in the ppk gene of six bacterial pathogens renders them greatly impaired in motility on semisolid agar plates; this defect can be corrected by the introduction of ppk gene in trans. In view of the fact that the motility of pathogens is essential to invade and establish systemic infections in host cells, this impairment in motility suggests a crucial and essential role of PPK or polyP in bacterial pathogenesis.

ppk基因编码多聚磷酸激酶（polyphosphate kinase, PPK），是多数细菌中以ATP为底物合成无机多聚磷酸盐（polyphosphate, polyP）的主要酶类。对六种细菌性病原体的ppk基因引入无效突变后，这些菌株在半固体琼脂平板上的运动能力会显著受损；该运动缺陷可通过反式导入ppk基因得到修复。鉴于病原体的运动能力对于入侵宿主细胞并建立全身性感染至关重要，这种运动能力受损的现象提示，PPK或polyP在细菌致病机制中发挥着关键且不可或缺的作用。