cumA, a gene encoding a multicopper oxidase, is involved in Mn2+ oxidation in Pseudomonas putida GB-1.
Pseudomonas putida GB-1-002 catalyzes the oxidation of Mn2+. Nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designated cumA) encoding a protein homologous to multicopper oxidases. Addition of Cu2+ increased the Mn2+-oxidizing activity of the P. putida wild type by a factor of approximately 5. The growth rates of the wild type and the mutant were not affected by added Cu2+. A second open reading frame (designated cumB) is located downstream from cumA. Both cumA and cumB probably are part of a single operon. The translation product of cumB was homologous (level of identity, 45%) to that of orf74 of Bradyrhizobium japonicum. A mutation in orf74 resulted in an extended lag phase and lower cell densities. Similar growth-related observations were made for the cumA mutant, suggesting that the cumA mutation may have a polar effect on cumB. This was confirmed by site-specific gene replacement in cumB. The cumB mutation did not affect the Mn2+-oxidizing ability of the organism but resulted in decreased growth. In summary, our data indicate that the multicopper oxidase CumA is involved in the oxidation of Mn2+ and that CumB is required for optimal growth of P. putida GB-1-002.
Brouwers
G J
GJ
Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, 2300 R.A. Leiden, The Netherlands. brouwers@chem.leidenuniv.nl
de Vrind
J P
JP
Corstjens
P L
PL
Cornelis
P
P
Baysse
C
C
de Vrind-de Jong
E W
EW
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D003300:Copper / Q000378:metabolism / Q000494:pharmacology; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D008345:Manganese / Q000378:metabolism*; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016958:Pseudomonas putida / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D017422:Sequence Analysis, DNA
D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D008345:Manganese; D003300:Copper; D010088:Oxidoreductases; C121475:cumA protein, Pseudomonas putida