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Proteasome; Inhibitor; Thermoplasma acidophilum; Archaea.; Degradation; Inhibitors.; Biochemistry & biophysics.
Abstract:
Hitherto the biology of proteolysis in prokaryotes, particularly in archaea, is only poorly understood. We hale used the tri-peptide vinyl sulfone inhibitor carboxybenzyl-leucyl-leucyl-leucine vinyl sulfone (Z-L-3 VS) to study the in vivo function of proteasomes in Thermoplasma acidophilum. Z-L-3 VS is a potent inhibitor of the Thermoplasma proteasome and is capable of modifying 75 to 80% of the proteasomal beta-subunits in cell cultures. Inhibition of proteasomes has only marginal effects under normal growth conditions. Under heat shock conditions, however, the effects of proteasome inhibition are much more severe, to the extent of complete cell growth arrest. These data suggest that other proteolytic systems may exist that can compensate for the loss of proteasome function in T. acidophilum. (C) 1998 Federation of European Biochemical Societies. [References: 25]
