Comparative proteomic analysis of Desulfovibrio vulgaris
EMSL Project ID
15891
Abstract
We propose to perform a semi-quantitative proteomic analysis of Desulfovibrio vulgaris, a model organism for sulfate-reducing bacteria, cultured under various environmental conditions. The sulfate-reducing bacteria are cosmopolitan to environmental niches that contain sulfate and important historical significance includes their corrosion of pipes and their ability to precipitate heavy metals and radionuclides from solution, such as U(VI) and Tc(VII) reduction. The research on this organism will expand our knowledge of its metabolic and regulatory network, and the mechanisms leading to the immobilization of various contaminants at the biomolecular level, which is the primary goal of the DOE Biomolecular Science and Engineering program. In the past two years, we have been collaborating with Drs. David Camp II and Richard Smith of EMSL for proteomic analysis of D. vulgaris under various growth and stress conditions using the Agilent LC-XCT ion trap instrument systems. Some major results were summarized below:
D. vulgaris grown on different carbon sources: For 4 different growth conditions initial proteomic analysis showed that most of the enzymes in the substrate-level phosphorylation and CO cycling were expressed at a low level, suggesting they might not be the primary pathways for ATP biosynthesis in the media. However, hydrogen cycling, with one of its key enzymes, the [NiFe] hydrogenase (HynA-1), highly expressed in all four experimental conditions, may be important for oxidation of H2 linked to the proton gradient in both lactate- and formate-based media. In addition, the results suggested that the proton gradient pathway catalyzed by alcohol dehydrogenases and heterodisulfide reductases might be actively functioning for ATP synthesis in D. vulgaris.
D. vulgaris growth under stress conditions: Preliminary results revealed increased expression of heat shock proteins such as chaperonin (GroEL and GroES), DanK, trigger factor (TF) and HtpG for both heat shock and oxidative stress conditions. In addition, the proteins with specific protective function against oxidative stress, such as nigerythrin (Ngr), desulfoferrodoxin (RbO), rubredoxin-oxygen oxidoreductase (RoO) , thioredoxin (Trx) and bacterioferritin proteins (Bfr), were found to be up-regulated by heat shock in D. vulgaris, suggesting that they may be involved in protection against heat shock as well. The initial results also showed that the enzymes involved in sulfate reduction and cysteine synthesis were up-regulated, which may increase the glutathione biosynthesis necessary to combat oxidative stress and heat shock.
To improve the overall proteome coverage and expand the look up table of highly confident peptide identifications in D. vulgaris and obtain semi-quantitative data for publication under a variety of environmental conditions, , we submit in this EMSL User Proposal additional strategic proteomics studies using the new LTQ-MS/MS instrumentation. These studies will provide new insights into the metabolic and regulatory network in D. vulgaris and increase the odds of funding in the GTL program in the near future. The deliverables at the end of this project include three manuscripts that will be submitted for publication.
Project Details
Project type
Exploratory Research
Start Date
2005-08-01
End Date
2006-07-14
Status
Closed
Released Data Link
Team
Principal Investigator