Blue-Native PAGE gel strips after formate dehydrogenase or hydrogenase activity staining.

Soluble or membrane proteins of butyrate- or crotonate-grown S. wolfei were separated by Blue-Native PAGE under anoxic conditions, and the individual lanes excised from the gels and submitted to formate dehydrogenase or hydrogenase activity staining when using formate or hydrogen gas as the electron donor, respectively, and the electron acceptor benzyl viologen as the stain. Stained bands were excised and analyzed by PF-MS in order to identify the corresponding formate dehydrogenase or hydrogenase catalytic subunits. The figure illustrates the endpoint of the staining and the formate dehydrogenase or hydrogenase catalytic subunits identified (locus tags and numbering of the catalytic subunits according to Sieber et al. [12]); for images showing the time course of the staining, and for details on the PF-MS identifications, see Figs. S3, S4, S5, S6 and Table S1 in the Supplemental information file, respectively. Legend: But and Crot, soluble or membrane proteins from butyrate- and crotonate-grown S. wolfei cells.