Coping with anoxia: a comprehensive proteomic and transcriptomic survey of denitrification.

Ralstonia eutropha H16 is a denitrifying microorganism able to use nitrate and nitrite as terminal electron acceptors under oxygen deprivation. To identify proteins showing an altered expression pattern in response to oxygen supply, R. eutropha cells grown aerobically and anaerobically were compared in a comprehensive proteome and transcriptome approach.

Analyses of soluble and membrane proteomes of Ralstonia eutropha H16 reveal major changes in the protein complement in adaptation to lithoautotrophy.

The soil-dwelling lithoautotrophic bacterium Ralstonia eutropha H16 utilizes hydrogen as the key source of energy during aerobic growth on hydrogen and carbon dioxide. We examined the soluble and membrane protein complements of lithoautotrophically grown cells and compared them to the protein complements of cells grown organoheterotrophically on succinate. (14)N/(15)N-based inverse metabolic labeling in combination with GeLC-MS led to the identification of 1452 proteins, 1174 of which could be quantitated.

A proteomic view of the facultatively chemolithoautotrophic lifestyle of Ralstonia eutropha H16.

Ralstonia eutropha H16 is an H(2)-oxidizing, facultative chemolithoautotroph. Using 2-DE in conjunction with peptide mass spectrometry we have cataloged the soluble proteins of this bacterium during growth on different substrates: (i) H(2) and CO(2), (ii) succinate and (iii) glycerol. The first and second conditions represent purely lithoautotrophic and purely organoheterotrophic nutrition, respectively.