Highlights of Research Progress
Measuring Differential Expression of Cytochromes in the Metal-Reducing Bacterium Geobacter
Microbial proteomics involves the comprehensive measurement of cellular proteins to achieve a fundamental understanding of cell processes. New and innovative separation and mass spectrometry technologies enable cellular proteins to be identified and their cellular location and relative abundance to be determined. Cytochromes are an important class of proteins involved in dissimilatory metal reduction in the membranes of the bacterium Geobacter sulfurreducens. As part of Genomics:GTL, cytochrome distribution is providing important insights into how this organism responds and adjusts its electron-transport system to different environmental stimuli. Global measurements led to the determination that the relative abundance of certain c-type cytochromes varied markedly during growth on Fe(III), indicating that they would play an essential role in Fe(III) reduction. Such global measurements are important for simultaneously characterizing microbial proteomes and for achieving a systems-level understanding of how microorganisms can be manipulated to achieve desired outcomes for bioremediation, energy production, or carbon sequestration. [Mary Lipton, Pacific Northwest National Laboratory, and Derek Lovley, University of Massachusetts]
