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Differential protein expression in the metal‐reducing bacterium Geobacter sulfurreducens strain PCA grown with fumarate or ferric citrate
Author(s) -
Khare Tripti,
EsteveNúñez Abraham,
Nevin Kelly P.,
Zhu Wenhong,
Yates John R.,
Lovley Derek,
Giometti Carol S.
Publication year - 2006
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200500137
Subject(s) - geobacter sulfurreducens , biochemistry , electron acceptor , chemistry , oxidoreductase , ferrous , rubredoxin , electron transport chain , superoxide dismutase , biology , bacteria , enzyme , biofilm , organic chemistry , genetics
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.