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Redundancy and modularity in membrane-associated dissimilatory nitrate reduction in Bacillus.

Heylen K, Keltjens J - Front Microbiol (2012)

Bottom Line: The genomes of two phenotypically denitrifying type strains of the genus Bacillus were sequenced and the pathways for dissimilatory nitrate reduction were reconstructed.In addition to the already characterized menaquinol/cyt c-dependent nitric oxide reductase (Suharti et al., 2001, 2004) of which the encoding genes could be identified now, evidence for another novel nitric oxide reductase (NOR) was found.Also, our analyses confirm earlier findings on branched electron transfer with both menaquinol and cytochrome c as reductants.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, University of Ghent Gent, Belgium.

ABSTRACT
The genomes of two phenotypically denitrifying type strains of the genus Bacillus were sequenced and the pathways for dissimilatory nitrate reduction were reconstructed. Results suggest that denitrification proceeds in the periplasmic space and in an analogous fashion as in Gram-negative organisms, yet with the participation of proteins that tend to be membrane-bound or membrane-associated. A considerable degree of functional redundancy was observed with marked differences between B. azotoformans LMG 9581(T) and B. bataviensis LMG 21833(T). In addition to the already characterized menaquinol/cyt c-dependent nitric oxide reductase (Suharti et al., 2001, 2004) of which the encoding genes could be identified now, evidence for another novel nitric oxide reductase (NOR) was found. Also, our analyses confirm earlier findings on branched electron transfer with both menaquinol and cytochrome c as reductants. Quite unexpectedly, both bacilli have the disposal of two parallel pathways for nitrite reduction enabling a life style as a denitrifier and as an ammonifying bacterium.

No MeSH data available.


Pathways and functional gene inventories for denitrification and ammonification in B. azotoformans LMG 9581T (A) and B. bataviensis LMG 21833T (B). Black ovals indicate predicted functional enzymes, gray ovals likely functional enzymes and white ovals pseudogenes or corrupted enzymes. NAR, cytoplasmic dissimilatory nitrate reductase; NAP, periplasmic dissimilatory nitrate reductase; NasC, assimilatory nitrate reductase; NrfHA, dissimilatory nitrite reductase to ammonium; NirBD, assimilatory nitrite reductase; NirK, periplasmic nitrite reductase to nitric oxide; qNor, dissimilatory quinol-dependent nitric oxide reductase; sNor, dissimilatory menaquinol/cyt c-dependent nitric oxide reductase; NosZ, dissimilatory nitrous oxide reductase. See text for more explanations.
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Figure 4: Pathways and functional gene inventories for denitrification and ammonification in B. azotoformans LMG 9581T (A) and B. bataviensis LMG 21833T (B). Black ovals indicate predicted functional enzymes, gray ovals likely functional enzymes and white ovals pseudogenes or corrupted enzymes. NAR, cytoplasmic dissimilatory nitrate reductase; NAP, periplasmic dissimilatory nitrate reductase; NasC, assimilatory nitrate reductase; NrfHA, dissimilatory nitrite reductase to ammonium; NirBD, assimilatory nitrite reductase; NirK, periplasmic nitrite reductase to nitric oxide; qNor, dissimilatory quinol-dependent nitric oxide reductase; sNor, dissimilatory menaquinol/cyt c-dependent nitric oxide reductase; NosZ, dissimilatory nitrous oxide reductase. See text for more explanations.

Mentions: Above, we made a comprehensive analysis of the functional denitrification gene inventory of two Bacillus species. Our results are schematically presented in Figure 4. Our exploration came with quite some surprises, we detected potential new enzymes, supported previous suggestions and raised interesting questions that need experimental answers, which we briefly would like to summarize.


Redundancy and modularity in membrane-associated dissimilatory nitrate reduction in Bacillus.

Heylen K, Keltjens J - Front Microbiol (2012)

Pathways and functional gene inventories for denitrification and ammonification in B. azotoformans LMG 9581T (A) and B. bataviensis LMG 21833T (B). Black ovals indicate predicted functional enzymes, gray ovals likely functional enzymes and white ovals pseudogenes or corrupted enzymes. NAR, cytoplasmic dissimilatory nitrate reductase; NAP, periplasmic dissimilatory nitrate reductase; NasC, assimilatory nitrate reductase; NrfHA, dissimilatory nitrite reductase to ammonium; NirBD, assimilatory nitrite reductase; NirK, periplasmic nitrite reductase to nitric oxide; qNor, dissimilatory quinol-dependent nitric oxide reductase; sNor, dissimilatory menaquinol/cyt c-dependent nitric oxide reductase; NosZ, dissimilatory nitrous oxide reductase. See text for more explanations.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475470&req=5

Figure 4: Pathways and functional gene inventories for denitrification and ammonification in B. azotoformans LMG 9581T (A) and B. bataviensis LMG 21833T (B). Black ovals indicate predicted functional enzymes, gray ovals likely functional enzymes and white ovals pseudogenes or corrupted enzymes. NAR, cytoplasmic dissimilatory nitrate reductase; NAP, periplasmic dissimilatory nitrate reductase; NasC, assimilatory nitrate reductase; NrfHA, dissimilatory nitrite reductase to ammonium; NirBD, assimilatory nitrite reductase; NirK, periplasmic nitrite reductase to nitric oxide; qNor, dissimilatory quinol-dependent nitric oxide reductase; sNor, dissimilatory menaquinol/cyt c-dependent nitric oxide reductase; NosZ, dissimilatory nitrous oxide reductase. See text for more explanations.
Mentions: Above, we made a comprehensive analysis of the functional denitrification gene inventory of two Bacillus species. Our results are schematically presented in Figure 4. Our exploration came with quite some surprises, we detected potential new enzymes, supported previous suggestions and raised interesting questions that need experimental answers, which we briefly would like to summarize.

Bottom Line: The genomes of two phenotypically denitrifying type strains of the genus Bacillus were sequenced and the pathways for dissimilatory nitrate reduction were reconstructed.In addition to the already characterized menaquinol/cyt c-dependent nitric oxide reductase (Suharti et al., 2001, 2004) of which the encoding genes could be identified now, evidence for another novel nitric oxide reductase (NOR) was found.Also, our analyses confirm earlier findings on branched electron transfer with both menaquinol and cytochrome c as reductants.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microbiology, Department of Biochemistry and Microbiology, University of Ghent Gent, Belgium.

ABSTRACT
The genomes of two phenotypically denitrifying type strains of the genus Bacillus were sequenced and the pathways for dissimilatory nitrate reduction were reconstructed. Results suggest that denitrification proceeds in the periplasmic space and in an analogous fashion as in Gram-negative organisms, yet with the participation of proteins that tend to be membrane-bound or membrane-associated. A considerable degree of functional redundancy was observed with marked differences between B. azotoformans LMG 9581(T) and B. bataviensis LMG 21833(T). In addition to the already characterized menaquinol/cyt c-dependent nitric oxide reductase (Suharti et al., 2001, 2004) of which the encoding genes could be identified now, evidence for another novel nitric oxide reductase (NOR) was found. Also, our analyses confirm earlier findings on branched electron transfer with both menaquinol and cytochrome c as reductants. Quite unexpectedly, both bacilli have the disposal of two parallel pathways for nitrite reduction enabling a life style as a denitrifier and as an ammonifying bacterium.

No MeSH data available.