Characterization of the proteasome from the extremely halophilic archaeonHaloarcula marismortui

A 20S proteasome, comprising two subunits α and β, was purified from the extreme halophilic archaeon Haloarcula marismortui , which grows only in saturated salt conditions. The three-dimensional reconstruction of the H. marismortui proteasome (Hm proteasome), obtained from negatively stained electron micrographs, is virtually identical to the structure of a thermophilic proteasome filtered to the same resolution. The stability of the Hm...