Part of a complex that catalyzes the reversible cleavage of acetyl-CoA, allowing growth on acetate as sole source of carbon and energy. The alpha-epsilon complex generates CO from CO(2), while the beta subunit (this protein) combines the CO with CoA and a methyl group to form acetyl-CoA. The methyl group, which is incorporated into acetyl-CoA, is transferred to the beta subunit by a corrinoid iron-sulfur protein (the gamma-delta complex). acetyl-CoA + Co(I)-[corrinoid Fe-S protein] + H(+) = CO + CoA + methyl-Co(III)-[corrinoid Fe-S protein] Binds 1 [Ni-Fe-S] cluster. One-carbon metabolism; methanogenesis from acetate. Monomer. The ACDS complex is made up of alpha, epsilon, beta, gamma and delta chains with a probable stoichiometry of (alpha(2)epsilon(2))(4)-beta(8)-(gamma(1)delta(1))(8) (Potential). Belongs to the CdhC family.