CHARACTERIZATION OF NUCLEOSIDE-DIPHOSPHATE KINASE FROM PSEUDOMONAS-AERUGINOSA - COMPLEX-FORMATION WITH SUCCINYL-COA SYNTHETASE

The enzyme nucleoside-diphosphate kinase (Ndk), responsible for the co nversion of (deoxy)ribonucleoside diphosphates to their corresponding triphosphates, has been purified from Pseudomonas aeruginosa. The N-te rminal 12 amino acid sequence of P. aeruginosa Ndk shows significant h omology with that of Myxococcus xanthus and that of Escherichia coli. Ndk enzyme activity is also associated with succinyl-CoA synthetase ac tivity 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 a ppears to undergo autophosphorylation in the presence of either ATP or GTP, although the presence of small amounts of Ndk activity may influ ence the level of such phosphorylation.