Figure 1: Specificity of the polyclonal serum used for immunolocalization. The slots depict crude extracts of the organisms after Western blotting of SDS gels and double-immunoperoxidase precipitation. All slots show the typical pattern of MCR. For most organisms (except Ms ma and Mt mb), only the two larger of the three MCR subunits are visible. When cells were grown on nickel-depleted media, the respective slot is marked with -Ni. The second slot (marked with an asterisk) shows a silver stained SDS-polyacrylamide gel of the purified enzyme. Mt mb: Methanothermobacter marburgensis, Mt wo: Methanothermobacter wolfei, Mc ma: Methanococcus maripaludis, Ms fr: Methanosarcina mazei (DSM 3318, formerly Methanosarcina frisia), Ms ma: Methanosarcina mazei (DSM 3647).