User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse




Journal Article

Proteasome from thermoplasma acidophilum - a threonine protease

There are no MPG-Authors available
There are no locators available
Fulltext (public)
There are no public fulltexts available
Supplementary Material (public)
There is no public supplementary material available

Seemüller, E., Lupas, A., Stock, D., Löwe, J., Huber, R., & Baumeister, W. (1995). Proteasome from thermoplasma acidophilum - a threonine protease. Science, 268(5210), 579-582.

Cite as: http://hdl.handle.net/11858/00-001M-0000-0010-733B-1
The catalytic mechanism of the 20S proteasome from the archaebacterium Thermoplasma acidophilum has been analyzed by site-directed mutagenesis of the beta subunit and by inhibitor studies. Deletion of the amino-terminal threonine or its mutation to alanine led to inactivation of the enzyme. Mutation of the residue to serine led to a fully active enzyme, which was over ten times more sensitive to the serine protease inhibitor 3,4-dichloroisocoumarin. In combination with the crystal structure of a proteasome-inhibitor complex, the data show that the nucleophilic attack is mediated by the amino-terminal threonine of processed beta subunits. The conservation pattern of this residue in eukaryotic sequences suggests that at least three of the seven eukaryotic beta-type subunit branches should be proteolytically inactive. [References: 60]