Protein Family Models

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]. [1]. 12486232. A polyphosphate kinase (PPK2) widely conserved in bacteria.. Zhang H, Ishige K, Kornberg A;. Proc Natl Acad Sci U S A 2002;99:16678-16683.. [2]. 12482933. Polyphosphate kinase (PPK2), a potent, polyphosphate-driven. generator of GTP.. Ishige K, Zhang H, Kornberg A;. Proc Natl Acad Sci U S A 2002;99:16684-16688.. [3]. 19001261. Polyphosphate-dependent synthesis of ATP and ADP by the family-2. polyphosphate kinases in bacteria.. Nocek B, Kochinyan S, Proudfoot M, Brown G, Evdokimova E,. Osipiuk J, Edwards AM, Savchenko A, Joachimiak A, Yakunin AF;. Proc Natl Acad Sci U S A. 2008;105:17730-17735. (from Pfam)

Date:

2024-08-14

polyphosphate kinase 2 (PPK2) family protein similar to bacteria PPK2 that catalyzes the polyP-dependent phosphorylation of nucleoside diphosphates (ADP, GDP) to nucleoside triphosphates

Date:

2017-10-25

Members of this protein family are designated polyphosphate kinase 2 (PPK2) after the characterized protein in Pseudomonas aeruginosa. This family comprises one of three well-separated clades in the larger family described by Pfam model PF03976. PA0141 from this family has been shown capable of operating in reverse, with GDP preferred (over ADP) as a substrate, producing GTP (or ATP) by transfer of a phosphate residue from polyphosphate. Most species with a member of this family also encode a polyphosphate kinase 1 (PPK1).

Gene:

ppk2

Date:

2024-07-09