thumbnail

Differential cytochrome content and reductase activity in Geospirillum barnesii strain SeS3

Archives of Microbiology

By:
, , , ,
DOI: 10.1007/s002030050408

Links

Abstract

The protein composition, cytochrome content, and reductase activity in the dissimilatory selenate-reducing bacterium Geospirillum barnesii strain SeS3, grown with thiosulfate, nitrate, selenate, or fumarate as the terminal electron acceptor, was investigated. Comparison of seven high-molecular-mass membrane proteins (105.3, 90.3, 82.6, 70.2, 67.4, 61.1, and 57.3 kDa) by SDS-PAGE showed that their detection was dependent on the terminal electron acceptor used. Membrane fractions from cells grown on thiosulfate contained a 70.2-kDa c-type cytochrome with absorbance maxima at 552, 522, and 421 nm. A 61.1-kDa c-type cytochrome with absorption maxima at 552, 523, and 423 nm was seen in membrane fractions from cells grown on nitrate. No c-type cytochromes were detected in membrane fractions of either selenate- or fumarate-grown cells. Difference spectra, however, revealed the presence of a cytochrome b554 (absorption maxima at 554, 523, and 422 nm) in membrane fractions from selenate-grown cells and a cytochrome b556 (absorption maxima at 556, 520, and 416 nm) in membrane fractions from fumarate-grown cells. Analysis of reductase activity in the different membrane fractions showed variability in substrate specificity. However, enzyme activity was greatest for the substrate on which the cells had been grown (e.g., membranes from nitrate-grown cells exhibited the greatest activity with nitrate). These results show that protein composition, cytochrome content, and reductase activity are dependent on the terminal electron acceptor used for growth.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Differential cytochrome content and reductase activity in Geospirillum barnesii strain SeS3
Series title:
Archives of Microbiology
DOI:
10.1007/s002030050408
Volume
167
Issue:
1
Year Published:
1997
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Archives of Microbiology
First page:
1
Last page:
5
Number of Pages:
5