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Identification, characterization, and classification of genes encoding perchlorate reductase.
Kelly S Bender1, Ching Shang, Romy Chakraborty
1Department of Microbiology, Southern Illinois University, Carbondale, IL 62901, USA. laurie@micro.siu.edu
Journal of Bacteriology
|July 21, 2005
Summary
Bacterial perchlorate reductase, essential for breaking down perchlorate, is encoded by pcrABCD genes. These genes are active only in anaerobic conditions and are distinct from nitrate reduction pathways.
Area of Science:
- Microbiology
- Environmental Science
- Biochemistry
Background:
- Perchlorate reduction is a critical step in the biodegradation of perchlorate, a pollutant.
- Perchlorate reductase (EC 1.97.1.1) catalyzes the initial enzymatic reduction of perchlorate to chlorite.
- Understanding the genetic basis of perchlorate reduction is vital for bioremediation strategies.
Purpose of the Study:
- To characterize the genes encoding perchlorate reductase (pcrABCD) in Dechloromonas species.
- To investigate the regulation and functional role of these genes in perchlorate metabolism.
- To differentiate perchlorate reductase from related enzymes like chlorate reductase.
Main Methods:
- Sequence analysis of pcrABCD genes.
- Gene expression analysis using Northern blotting or RT-PCR.
- Gene deletion experiments in Dechloromonas aromatica.
- Phylogenetic analysis and DNA hybridization.
Main Results:
- pcrAB genes show similarity to subunits of microbial DMSO reductase family enzymes.
- pcrC encodes a c-type cytochrome, and pcrD encodes a molybdenum chaperone.
- pcrA expression is strictly anaerobic and repressed by oxygen.
- Deletion of pcrA abolishes growth on perchlorate and chlorate but not nitrate.
- Phylogenetic and hybridization analyses confirm perchlorate reductase is distinct from chlorate reductase.
Conclusions:
- The pcrABCD genes encode a functional perchlorate reductase enzyme system.
- Perchlorate reductase activity is regulated by oxygen and is separate from nitrate reduction.
- Perchlorate reductase represents a distinct enzyme class within the DMSO reductase family.