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Medientyp:
E-Artikel
Titel:
cumA , a Gene Encoding a Multicopper Oxidase, Is Involved in Mn 2+ Oxidation in Pseudomonas putida GB-1
Beteiligte:
Brouwers, Geert-Jan;
de Vrind, Johannes P. M.;
Corstjens, Paul L. A. M.;
Cornelis, Pierre;
Baysse, Christine;
de Vrind-de Jong, Elisabeth W.
Erschienen:
American Society for Microbiology, 1999
Erschienen in:Applied and Environmental Microbiology
Beschreibung:
<jats:title>ABSTRACT</jats:title>
<jats:p>
<jats:italic>Pseudomonas putida</jats:italic>
GB-1-002 catalyzes the oxidation of Mn
<jats:sup>2+</jats:sup>
. Nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designated
<jats:italic>cumA</jats:italic>
) encoding a protein homologous to multicopper oxidases. Addition of Cu
<jats:sup>2+</jats:sup>
increased the Mn
<jats:sup>2+</jats:sup>
-oxidizing activity of the
<jats:italic>P. putida</jats:italic>
wild type by a factor of approximately 5. The growth rates of the wild type and the mutant were not affected by added Cu
<jats:sup>2+</jats:sup>
. A second open reading frame (designated
<jats:italic>cumB</jats:italic>
) is located downstream from
<jats:italic>cumA</jats:italic>
. Both
<jats:italic>cumA</jats:italic>
and
<jats:italic>cumB</jats:italic>
probably are part of a single operon. The translation product of
<jats:italic>cumB</jats:italic>
was homologous (level of identity, 45%) to that of
<jats:italic>orf74</jats:italic>
of
<jats:italic>Bradyrhizobium japonicum</jats:italic>
. A mutation in
<jats:italic>orf74</jats:italic>
resulted in an extended lag phase and lower cell densities. Similar growth-related observations were made for the
<jats:italic>cumA</jats:italic>
mutant, suggesting that the
<jats:italic>cumA</jats:italic>
mutation may have a polar effect on
<jats:italic>cumB</jats:italic>
. This was confirmed by site-specific gene replacement in
<jats:italic>cumB</jats:italic>
. The
<jats:italic>cumB</jats:italic>
mutation did not affect the Mn
<jats:sup>2+</jats:sup>
-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 Mn
<jats:sup>2+</jats:sup>
and that CumB is required for optimal growth of
<jats:italic>P. putida</jats:italic>
GB-1-002.
</jats:p>