The basic function of respiratory electron transport in any living organism is to generate a transmembrane electrochemical gradient that is used to drive ATP synthesis. Coupling the energetically favorable oxidation of various substrates with the unfavorable transport of protons helps drive gradient formation. Oxidation of substrates and catalysis of electron transfer is carried out by a group of membrane-associated proteins, which together define the respiratory chain of a cell.
Bacteria make useful models for studying electron transport.
The bacterium we use for our work is Rhodobacter sphaeroides . This Gram negative photosynthetic heterotroph provides a rich field for study because of its physiological diversity. Respiration driven phosphorylation occurs either aerobically or anaerobically in this bacterium. My lab focuses on a form of anaerobic respiration termed denitrification. Denitrification is the reduction of nitrate to gaseous nitrogen end products, principally nitrogen gas.