Differential protein expression in the metal-reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate.

TitleDifferential protein expression in the metal-reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate.
Publication TypeJournal Article
Year of Publication2006
AuthorsKhare T, Esteve-Núñez A, Nevin KP, Zhu W, Yates JR, Lovley D, Giometti CS
JournalProteomics
Volume6
Issue2
Pagination632-40
Date Published2006 Jan
ISSN1615-9853
KeywordsAnaerobiosis, Bacterial Proteins, Electrophoresis, Gel, Two-Dimensional, Ferric Compounds, Fumarates, Geobacter, Oxidation-Reduction, Proteomics, Reactive Oxygen Species, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Abstract

Geobacter sulfurreducens, generally considered to be a strict anaerobe, is a predominant microbe in subsurface environments, where it utilizes available metals as electron acceptors. To better understand the metabolic processes involved in the metal-reduction capability of this microbe, the proteins expressed by cells grown anaerobically with either fumarate or ferric citrate as electron acceptor were compared. Proteins were separated by 2-DE under denaturing or nondenaturing conditions, and proteins varying in abundance with a high level of statistical significance (p<0.0001) were identified by peptide mass analysis. Denaturing 2-DE revealed significant differences in the relative abundance of the membrane proteins OmpA and peptidoglycan-associated lipoprotein, several metabolic enzymes, and, in addition, superoxide dismutase and rubredoxin oxidoreductase. Nondenaturing 2-DE revealed elevated catalase in cells grown with ferric citrate. These results suggest that, in addition to adjustments in membrane transport and specific metabolic pathways in response to these two different electron acceptors, distinct differences exist in the oxidative environment within the cell when fumarate or soluble ferric citrate is provided as electron acceptor. Although an anaerobe, G. sulfurreducens appears to have alternate mechanisms for dealing with reactive oxygen species in response to increased intracellular soluble iron.

DOI10.1002/pmic.200500137
Alternate JournalProteomics
PubMed ID16342140