Figure 1. Experimental design of the differential proteomics approach used in this study.

Grown cultures of S. multivorans were harvested and prepared for LC-MS measurement after repeated transfers (10% inoculum) on the desired substrates (Py, pyruvate; Fo, formate; Fu, fumarate; Ni, nitrate; PCE, tetrachloroethene) to get rid of any residual amounts of previously applied electron acceptors. The initial 60 transfers on Py/Fu were carried out to achieve down-regulation of PCE respiration in S. multivorans cells¹². Membrane protein extract (ME) and soluble protein fraction (SF) were subjected to 1D-SDS PAGE. After in-gel digestion, peptide lysates were analyzed by LC-MS.