Subunit topology of two 20S proteasomes from Haloferax volcanii.

ABSTRACT: Haloferax volcanii, a halophilic archaeon, synthesizes three different proteins (alpha1, alpha2, and beta) which are classified in the 20S proteasome superfamily. The alpha1 and beta proteins alone form active 20S proteasomes; the role of alpha2, however, is not clear. To address this, alpha2 was synthesized with an epitope tag and purified by affinity chromatography from recombinant H. volcanii. The alpha2 protein copurified with alpha1 and beta in a complex with an overall structure and peptide-hydrolyzing activity comparable to those of the previously described alpha1-beta proteasome. Supplementing buffers with 10 mM CaCl(2) stabilized the halophilic proteasomes in the absence of salt and enabled them to be separated by native gel electrophoresis. This facilitated the discovery that wil

SUBMITTER: Kaczowka SJ 

PROVIDER: S-EPMC141826 | biostudies-literature | 2003 Jan

REPOSITORIES: biostudies-literature