A multicopper oxidase is essential for manganese oxidation and laccase-like activity in Pedomicrobium sp. ACM 3067.
Pedomicrobium sp. ACM 3067 is a budding-hyphal bacterium belonging to the alpha-Proteobacteria which is able to oxidize soluble Mn2+ to insoluble manganese oxide. A cosmid, from a whole-genome library, containing the putative genes responsible for manganese oxidation was identified and a primer-walking approach yielded 4350 bp of novel sequence. Analysis of this sequence showed the presence of a predicted three-gene operon, moxCBA. The moxA gene product showed homology to multicopper oxidases (MCOs) and contained the characteristic four copper-binding motifs (A, B, C and D) common to MCOs. An insertion mutation of moxA showed that this gene was essential for both manganese oxidation and laccase-like activity. The moxB gene product showed homology to a family of outer membrane proteins which are essential for Type I secretion in Gram-negative bacteria. moxBA has not been observed in other manganese-oxidizing bacteria but homologues were identified in the genomes of several bacteria including Sinorhizobium meliloti 1021 and Agrobacterium tumefaciens C58. These results suggest that moxBA and its homologues constitute a family of genes encoding an MCO and a predicted component of the Type I secretion system.
Ridge
Justin P
JP
Centre for Bacterial Diversity and Identification, University of Queensland, St. Lucia, Qld 4072, Australia.
Lin
Marianne
M
Larsen
Eloise I
EI
Fegan
Mark
M
McEwan
Alastair G
AG
Sly
Lindsay I
LI
D020561:Alphaproteobacteria / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D003360:Cosmids / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D042845:Laccase / Q000145:classification / Q000235:genetics / Q000378:metabolism; D008345:Manganese / Q000378:metabolism*; D009876:Operon / Q000235:genetics*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017422:Sequence Analysis, DNA
D004269:DNA, Bacterial; D008345:Manganese; D003300:Copper; D010088:Oxidoreductases; D042845:Laccase