Purification and Characterization of (Per)Chlorate Reductase from the Chlorate-Respiring Strain GR-1
AUTOR(ES)
Kengen, Servé W. M.
FONTE
American Society for Microbiology
RESUMO
Strain GR-1 is one of several recently isolated bacterial species that are able to respire by using chlorate or perchlorate as the terminal electron acceptor. The organism performs a complete reduction of chlorate or perchlorate to chloride and oxygen, with the intermediate formation of chlorite. This study describes the purification and characterization of the key enzyme of the reductive pathway, the chlorate and perchlorate reductase. A single enzyme was found to catalyze both the chlorate- and perchlorate-reducing activity. The oxygen-sensitive enzyme was located in the periplasm and had an apparent molecular mass of 420 kDa, with subunits of 95 and 40 kDa in an α3β3 composition. Metal analysis showed the presence of 11 mol of iron, 1 mol of molybdenum, and 1 mol of selenium per mol of heterodimer. In accordance, quantitative electron paramagnetic resonance spectroscopy showed the presence of one [3Fe-4S] cluster and two [4Fe-4S] clusters. Furthermore, two different signals were ascribed to Mo(V). The Kmvalues for perchlorate and chlorate were 27 and <5 μM, respectively. Besides perchlorate and chlorate, nitrate, iodate, and bromate were also reduced at considerable rates. The resemblance of the enzyme to nitrate reductases, formate dehydrogenases, and selenate reductase is discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94135Documentos Relacionados
- Kinetics of Perchlorate- and Chlorate-Respiring Bacteria
- Characterization of the Chlorate Reductase from Pseudomonas chloritidismutans
- Purification and Characterization of the Nitrate Reductase from the Diatom Thalassiosira pseudonana1
- SOME RESPONSES OF THE BEAN PLANT TO CHLORATE AND PERCHLORATE IONS
- Purification and characterization of phenylacetaldehyde reductase from a styrene-assimilating Corynebacterium strain, ST-10.