ALGINATE, INORGANIC POLYPHOSPHATE, GTP AND PPGPP SYNTHESIS COREGULATED IN PSEUDOMONAS-AERUGINOSA - IMPLICATIONS FOR STATIONARY-PHASE SURVIVAL AND SYNTHESIS OF RNA DNA PRECURSORS/

The regulatory protein AlgR2 in Pseudomonas aeruginosa positively regu lates nucleoside diphosphate kinase (Ndk) and succinyl-CoA synthetase, enzymes critical in nucleoside triphosphate (NTP) formation. AlgRS po sitively regulates the production of alginate, GTP, ppGpp and inorgani c polyphosphate (poly P). An algR2 mutant with low levels of these met abolites has them restored by introducing and overexpressing either th e algR2 or the ndk gene into the algR2 mutant. Thus, Ndk is involved i n the formation of these compounds and largely prevents the death of t he algR2 mutant, which occurs early in the stationary phase. We demons trate that the 12 kDa Ndk-pyruvate kinase (Pk) complex, previously sho wn to generate predominantly GTP instead of all the NTPs, has a low af finity for the deoxynucleoside diphosphates and cannot generate the dN TPs needed for DNA replication and cell division; this complex may thu s be involved in regulating the levels of both NTPs and dNTPs that mod ulate cell division and survival in the stationary phase.