Metagenomic and biochemical characterizations of sulfur oxidation metabolism in uncultured large sausage-shaped bacterium in hot spring microbial mats

So-called "sulfur-turf" microbial mats in sulfide containing hot springs (55-70°C, pH 7.3-8.3) in Japan were dominated by a large sausage-shaped bacterium (LSSB) that is closely related to the genus Sulfurihydrogenibium. Several previous reports proposed that the LSSB would be involved in...

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Bibliographic Details
Published in:PloS one 2012-11, Vol.7 (11), p.e49793
Main Authors: Tamazawa, Satoshi, Takasaki, Kazuto, Tamaki, Hideyuki, Kamagata, Yoichi, Hanada, Satoshi
Format: Article
Language:English
Subjects:
Analysis
Annotations
Aquificae
Bacteria
Bacteria - classification
Bacteria - enzymology
Bacteria - genetics
Bacteria - isolation & purification
Biochemical analysis
Biochemistry
Biology
Cytochrome
Dehydrogenase
Dehydrogenases
Deoxyribonucleic acid
DNA
E coli
Ecosystems
Energy resources
Environmental conditions
Environmental science
Enzymes
Fragments
Genes
Genomes
Genomics
Hot Springs
Japan
Mats
Metabolism
Metagenomics
Microbial mats
Microorganisms
Nucleotide sequence
Oxidation
Oxidation-Reduction
Oxidation-reduction reactions
pH effects
Phylogeny
Quinone
Quinone Reductases - genetics
Quinone Reductases - metabolism
Quinones
Reductase
RNA, Ribosomal, 16S - genetics
Sausage
Sequence Analysis, DNA
Studies
Sulfide
Sulfide-quinone reductase
Sulfides
Sulfides - metabolism
Sulfite
Sulfite dehydrogenase
Sulfite Dehydrogenase - genetics
Sulfite Dehydrogenase - metabolism
Sulfites
Sulfur
Sulfur oxidation
Sulfur Oxides - metabolism
Turf
Water springs
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Summary:So-called "sulfur-turf" microbial mats in sulfide containing hot springs (55-70°C, pH 7.3-8.3) in Japan were dominated by a large sausage-shaped bacterium (LSSB) that is closely related to the genus Sulfurihydrogenibium. Several previous reports proposed that the LSSB would be involved in sulfide oxidation in hot spring. However, the LSSB has not been isolated yet, thus there has been no clear evidence showing whether it possesses any genes and enzymes responsible for sulfide oxidation. To verify this, we investigated sulfide oxidation potential in the LSSB using a metagenomic approach and subsequent biochemical analysis. Genome fragments of the LSSB (a total of 3.7 Mb sequence including overlapping fragments) were obtained from the metagenomic fosmid library constructed from genomic DNA of the sulfur-turf mats. The sequence annotation clearly revealed that the LSSB possesses sulfur oxidation-related genes coding sulfide dehydrogenase (SD), sulfide-quinone reductase and sulfite dehydrogenase. The gene encoding SD, the key enzyme for sulfide oxidation, was successfully cloned and heterologously expressed in Escherichia coli. The purified recombinant enzyme clearly showed SD activity with optimum temperature and pH of 60°C and 8.0, respectively, which were consistent with the environmental conditions in the hot spring where the sulfur-turf thrives. Furthermore, the affinity of SD to sulfide was relatively high, which also reflected the environment where the sulfide could be continuously supplied. This is the first report showing that the LSSB harbors sulfide oxidizing metabolism adapted to the hot spring environment and can be involved in sulfide oxidation in the sulfur-turf microbial mats.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0049793