Document Detail


Elimination of manganese(II,III) oxidation in Pseudomonas putida GB-1 by a double knockout of two putative multicopper oxidase genes.
MedLine Citation:
PMID:  23124227     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Bacterial manganese(II) oxidation impacts the redox cycling of Mn, other elements, and compounds in the environment; therefore, it is important to understand the mechanisms of and enzymes responsible for Mn(II) oxidation. In several Mn(II)-oxidizing organisms, the identified Mn(II) oxidase belongs to either the multicopper oxidase (MCO) or the heme peroxidase family of proteins. However, the identity of the oxidase in Pseudomonas putida GB-1 has long remained unknown. To identify the P. putida GB-1 oxidase, we searched its genome and found several homologues of known or suspected Mn(II) oxidase-encoding genes (mnxG, mofA, moxA, and mopA). To narrow this list, we assumed that the Mn(II) oxidase gene would be conserved among Mn(II)-oxidizing pseudomonads but not in nonoxidizers and performed a genome comparison to 11 Pseudomonas species. We further assumed that the oxidase gene would be regulated by MnxR, a transcription factor required for Mn(II) oxidation. Two loci met all these criteria: PputGB1_2447, which encodes an MCO homologous to MnxG, and PputGB1_2665, which encodes an MCO with very low homology to MofA. In-frame deletions of each locus resulted in strains that retained some ability to oxidize Mn(II) or Mn(III); loss of oxidation was attained only upon deletion of both genes. These results suggest that PputGB1_2447 and PputGB1_2665 encode two MCOs that are independently capable of oxidizing both Mn(II) and Mn(III). The purpose of this redundancy is unclear; however, differences in oxidation phenotype for the single mutants suggest specialization in function for the two enzymes.
Authors:
Kati Geszvain; James K McCarthy; Bradley M Tebo
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2012-11-02
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  79     ISSN:  1098-5336     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2012-12-20     Completed Date:  2013-05-17     Revised Date:  2013-07-11    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  357-66     Citation Subset:  IM    
Affiliation:
Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Beaverton, Oregon, USA. geszvaik@ebs.ogi.edu
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MeSH Terms
Descriptor/Qualifier:
Gene Knockout Techniques*
Manganese / metabolism*
Oxidation-Reduction
Oxidoreductases / genetics*
Pseudomonas putida / enzymology*,  genetics,  metabolism*
Grant Support
ID/Acronym/Agency:
ES10337/ES/NIEHS NIH HHS
Chemical
Reg. No./Substance:
7439-96-5/Manganese; EC 1.-/Oxidoreductases
Comments/Corrections

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