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Title: The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism

Abstract

The role of tetraheme cytochrome c3 (CycA) in the metabolism of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough (DvH) was investigated by deletion of the cycA gene using a marker-exchange deletion strategy. A highly abundant periplasmic cytochrome, CycA has the important function of transferring electrons from periplasmic hydrogenases (Hyd, Hyn, Hys) to transmembrane complexes which transport the electrons to the cytoplasm where sulfate is reduced. Previous studies have indicated that during its interaction with periplasmic hydrogenases, CycA is also involved in the reduction of toxic metals. Growth of the cycA mutant strain on lactate as the electron donor and sulfate as the terminal electron acceptor showed that, despite its abundance, CycA is not essential for DvH growth. However, the rate of growth of the mutant strain was significantly lower, and the extent of growth less, than rates and extents of growth of the wild type and complement strains on lactate/sulfate medium. This indicates that a portion of the electrons generated from cytoplasmic lactate oxidation are transported by CycA for energy production, possibly in a hydrogen cycling mechanism employed to generate ATP. Failure of the mutant strain to grow on either formate or H2, with sulfate or sulfite as electron acceptors, furthermore » indicated that CycA may be the only redox partner of periplasmic hydrogenases. The cycA mutant strain also did not grow as well as either the wild type or complement strains on medium supplemented with pyruvate/sulfate. Final growth on pyruvate/sulfate was comparable, but the mutant grew more slowly than the wild type and complement strains. Interestingly, the mutant grew better than the wild type or complement strains on pyruvate alone, possibly due to the release of H2 and/or CO2 in concentrations which may be somewhat inhibitory to wild type growth.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Physical Biosciences Division
OSTI Identifier:
986247
Report Number(s):
LBNL-3806E-Poster
TRN: US201017%%268
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Technical Report
Resource Relation:
Conference: 110th General Meeting of the American Society for Microbiology, San Diego, CA
Country of Publication:
United States
Language:
English
Subject:
59; ABUNDANCE; BINDING ENERGY; CYTOCHROMES; CYTOPLASM; DESULFOVIBRIO; ELECTRONS; FORMATES; GENES; HYDROGEN; HYDROGENASES; LACTATES; METABOLISM; MUTANTS; OXIDATION; STRAINS; SULFATES; SULFITES; VALENCE; tetraheme cytochrome c3 (CycA), Desulfovibrio vulgaris Hildenborough (DvH)

Citation Formats

Semkiw, Elizabeth, Zane, Grant, and Wall, Judy. The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism. United States: N. p., 2010. Web. doi:10.2172/986247.
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Semkiw, Elizabeth, Zane, Grant, & Wall, Judy. The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism. United States. doi:10.2172/986247.
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Semkiw, Elizabeth, Zane, Grant, and Wall, Judy. Mon . "The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism". United States. doi:10.2172/986247. https://www.osti.gov/servlets/purl/986247.
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@article{osti_986247,
title = {The Role of the Tetraheme Cytochrome c3 in Desulfovibrio vulgaris Hildenborough Metabolism},
author = {Semkiw, Elizabeth and Zane, Grant and Wall, Judy},
abstractNote = {The role of tetraheme cytochrome c3 (CycA) in the metabolism of the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough (DvH) was investigated by deletion of the cycA gene using a marker-exchange deletion strategy. A highly abundant periplasmic cytochrome, CycA has the important function of transferring electrons from periplasmic hydrogenases (Hyd, Hyn, Hys) to transmembrane complexes which transport the electrons to the cytoplasm where sulfate is reduced. Previous studies have indicated that during its interaction with periplasmic hydrogenases, CycA is also involved in the reduction of toxic metals. Growth of the cycA mutant strain on lactate as the electron donor and sulfate as the terminal electron acceptor showed that, despite its abundance, CycA is not essential for DvH growth. However, the rate of growth of the mutant strain was significantly lower, and the extent of growth less, than rates and extents of growth of the wild type and complement strains on lactate/sulfate medium. This indicates that a portion of the electrons generated from cytoplasmic lactate oxidation are transported by CycA for energy production, possibly in a hydrogen cycling mechanism employed to generate ATP. Failure of the mutant strain to grow on either formate or H2, with sulfate or sulfite as electron acceptors, further indicated that CycA may be the only redox partner of periplasmic hydrogenases. The cycA mutant strain also did not grow as well as either the wild type or complement strains on medium supplemented with pyruvate/sulfate. Final growth on pyruvate/sulfate was comparable, but the mutant grew more slowly than the wild type and complement strains. Interestingly, the mutant grew better than the wild type or complement strains on pyruvate alone, possibly due to the release of H2 and/or CO2 in concentrations which may be somewhat inhibitory to wild type growth.},
doi = {10.2172/986247},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 17 00:00:00 EDT 2010},
month = {Mon May 17 00:00:00 EDT 2010}
}
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Technical Report:
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DOI:  10.2172/986247
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  • ; ; ; ...
    Desulfovibrio vulgaris is an anaerobic sulfate-reducing bacterium capable of facilitating the removal of toxic metals such as uranium from contaminated sites via reduction. As such, it is essential to understand the intricate regulatory cascades involved in how D. vulgaris and its relatives respond to stressors in such sites. One approach is the identification and analysis of small non-coding RNAs (sRNAs); molecules ranging in size from 20-200 nucleotides that predominantly affect gene regulation by binding to complementary mRNA in an anti-sense fashion and therefore provide an immediate regulatory response. To identify sRNAs in D. vulgaris, a bacterium that does not possessmore » an annotated hfq gene, RNA was pooled from stationary and exponential phases, nitrate exposure, and biofilm conditions. The subsequent RNA was size fractionated, modified, and converted to cDNA for high throughput transcriptomic deep sequencing. A computational approach to identify sRNAs via the alignment of seven separate Desulfovibrio genomes was also performed. From the deep sequencing analysis, 2,296 reads between 20 and 250 nt were identified with expression above genome background. Analysis of those reads limited the number of candidates to ~;;87 intergenic, while ~;;140 appeared to be antisense to annotated open reading frames (ORFs). Further BLAST analysis of the intergenic candidates and other Desulfovibrio genomes indicated that eight candidates were likely portions of ORFs not previously annotated in the D. vulgaris genome. Comparison of the intergenic and antisense data sets to the bioinformatical predicted candidates, resulted in ~;;54 common candidates. Current approaches using Northern analysis and qRT-PCR are being used toverify expression of the candidates and to further develop the role these sRNAs play in D. vulgaris regulation.« less

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  • ; ; - Journal of Bacteriology; (USA)
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