Genetic determinants of a nickel-specific transport system are part of the plasmid-encoded hydrogenase gene cluster in Alcaligenes eutrophus.
Nickel-deficient (Nic-) mutants of Alcaligenes eutrophus requiring high levels of nickel ions for autotrophic growth with hydrogen were characterized. The Nic- mutants carried defined deletions in the hydrogenase gene cluster of the indigenous pHG megaplasmid. Nickel deficiency correlated with a low level of the nickel-containing hydrogenase activity, a slow rate of nickel transport, and reduced activity of urease. The Nic+ phenotype was restored by a cloned DNA sequence (hoxN) of a megaplasmid pHG1 DNA library of A. eutrophus H16. hoxN is part of the hydrogenase gene cluster. The nickel requirement of Nic- mutants was enhanced by increasing the concentration of magnesium. This suggests that the Nic- mutants are impaired in the nickel-specific transport system and thus depend on the second transport activity which normally mediates the uptake of magnesium.
Eberz
G
G
Institut für Pflanzenphysiologie, Zellbiologie und Mikrobiologie, Freien Universität Berlin, Federal Republic of Germany.
Eitinger
T
T
Friedrich
B
B
D000421:Alcaligenes / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D005796:Genes; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006864:Hydrogenase / Q000235:genetics*; D007700:Kinetics; D005810:Multigene Family; D009154:Mutation; D009532:Nickel / Q000378:metabolism; D010957:Plasmids; D015183:Restriction Mapping
D009532:Nickel; D006864:Hydrogenase