Rashid M H, Kornberg A
Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305-5307, USA.
Proc Natl Acad Sci U S A. 2000 Apr 25;97(9):4885-90. doi: 10.1073/pnas.060030097.
Polyphosphate kinase (PPK), encoded by the ppk gene, is the principal enzyme in many bacteria for the synthesis of inorganic polyphosphate (poly P) from ATP. A knockout mutant in the ppk gene of Pseudomonas aeruginosa PAO1 is impaired in flagellar swimming motility on semisolid agar plates. The mutant is deficient in type IV pili-mediated twitching motility and in a "swarming motility" previously unobserved in P. aeruginosa. In swarming cultures, the polar monotrichous bacteria have differentiated into elongated and polar multitrichous cells that navigate the surface of solid media. All of the motility defects in the ppk mutant could be complemented by a plasmid harboring the ppk gene. Because bacterial motility is often crucial for their survival in a natural environment and for systemic infection inside a host, the dependence for motility on PPK reveals important roles for poly P in diverse processes such as biofilm formation, symbiosis, and virulence.
由ppk基因编码的多聚磷酸激酶（PPK）是许多细菌中利用ATP合成无机多聚磷酸（多聚P）的主要酶。铜绿假单胞菌PAO1的ppk基因敲除突变体在半固体琼脂平板上的鞭毛游动运动能力受损。该突变体在IV型菌毛介导的颤动运动以及铜绿假单胞菌中以前未观察到的“群体运动”方面存在缺陷。在群体培养中，极生单鞭毛细菌已分化为细长的极生多鞭毛细胞，这些细胞在固体培养基表面移动。ppk突变体中的所有运动缺陷都可以由携带ppk基因的质粒互补。由于细菌运动通常对它们在自然环境中的生存以及在宿主体内的全身感染至关重要，因此运动对PPK的依赖性揭示了多聚P在生物膜形成、共生和毒力等多种过程中的重要作用。
