Characterization of nucleoside-diphosphate kinase from Pseudomonas aeruginosa: complex formation with succinyl-CoA synthetase.

The enzyme nucleoside-diphosphate kinase (Ndk), responsible for the conversion of (deoxy)ribonucleoside diphosphates to their corresponding triphosphates, has been purified from Pseudomonas aeruginosa. The N-terminal 12 amino acid sequence of P. aeruginosa Ndk shows significant homology with that of Myxococcus xanthus and that of Escherichia coli. Ndk enzyme activity is also associated with succinyl-CoA synthetase activity in P. aeruginosa, whose alpha and beta subunits show extensive sequence homology with those of E. coli and Dictyostelium discoideum. The 33-kDa alpha subunit of succinyl-CoA synthetase of P. aeruginosa appears to undergo autophosphorylation in the presence of either ATP or GTP, although the presence of small amounts of Ndk activity may influence the level of such phosphorylation.