Localization of carbon monoxide dehydrogenase in acetate-adapted Methanosarcina barkeri

Immunogold labeling techniques were utilized to determine the cellular location of carbon monoxide dehydrogenase in the methanogenic bacterium Methanosarcina barkeri grown on acetate to enhance levels of the enzyme. Formaldehyde fixation followed by dehydration in methanol and embedment in Lowicryl K4M resin preserved the antigens. Sections were labelled with primary polyclonal rabbit antibody followed by protein A - gold. Low levels of labeling were improved by use of an antibody to protein A followed by a second incubation on protein A - gold. The enzyme is primarily located in the cytoplasm, which agrees with biochemical results showing that it resides in the soluble cellular fraction.Key words: Methanosarcina barkeri, methanogen, methanogenesis, enzyme localization, immunogold.