Inorganic polyphosphate (polyP) plays a role in metabolism and regulation and has been proposed to serve as a energy source in a pre-ATP world. In prokaryotes, the synthesis and utilisation of polyP are catalysed by PPK1, PPK2 and polyphosphatases. ...
Inorganic polyphosphate (polyP) plays a role in metabolism and regulation and has been proposed to serve as a energy source in a pre-ATP world. In prokaryotes, the synthesis and utilisation of polyP are catalysed by PPK1, PPK2 and polyphosphatases. Proteins with a single PPK2 domain catalyse polyP-dependent phosphorylation of ADP to ATP, whereas proteins containing 2 fused PPK2 domains phosphorylate AMP to ADP. The structure of PPK2 from Pseudomonas aeruginosa has revealed a a 3-layer alpha/beta/alpha sandwich fold with an alpha-helical lid similar to the structures of microbial thymidylate kinases [3].
