Part of the ACDS complex that catalyzes the reversible cleavage of acetyl-CoA, allowing autotrophic growth from CO(2). The alpha-epsilon subcomponent functions as a carbon monoxide dehydrogenase. Belongs to the Ni-containing carbon monoxide dehydrogenase family. This protein lacks several conserved Cys residues that bind [4Fe-4S] clusters in other CODHs. Therefore, it is not clear whether this protein is active. However, the protein would be able to bind a [Ni-4Fe-4S] cluster, which is the active site of CO oxidation.