skip to main content
Language:
Search Limited to: Search Limited to: Resource type Show Results with: Show Results with: Index

The caspase-like sites of proteasomes, their substrate specificity, new inhibitors and substrates, and allosteric interactions with the trypsin-like sites

Kisselev, Alexei F ; Garcia-Calvo, Margarita ; Overkleeft, Herman S ; Peterson, Erin ; Pennington, Michael W ; Ploegh, Hidde L ; Thornberry, Nancy A ; Goldberg, Alfred L

The Journal of biological chemistry, 19 September 2003, Vol.278(38), pp.35869-77 [Peer Reviewed Journal]

Full text available

View all versions
Citations Cited by
  • Title:
    The caspase-like sites of proteasomes, their substrate specificity, new inhibitors and substrates, and allosteric interactions with the trypsin-like sites
  • Author: Kisselev, Alexei F ; Garcia-Calvo, Margarita ; Overkleeft, Herman S ; Peterson, Erin ; Pennington, Michael W ; Ploegh, Hidde L ; Thornberry, Nancy A ; Goldberg, Alfred L
  • Description: Proteasomes are the primary sites for protein degradation in mammalian cells. Each proteasome particle contains two chymotrypsin-like, two trypsin-like, and two caspase-like proteolytic sites. Previous studies suggest a complex network of allosteric interactions between these catalytic and multiple regulatory sites. We used positional scanning combinatorial substrate libraries to determine the extended substrate specificity of the caspase-like sites. Based on this analysis, several new substrates were synthesized, the use of which confirmed earlier observations that caspase-like sites (often termed postglutamyl peptide hydrolase) cleave after aspartates better than after glutamates. Highly selective inhibitors of the caspase-like sites were also generated. They stimulated trypsin-like activity of yeast 20 S proteasomes up to 3-fold but not when binding of the inhibitor to the caspase-like sites was prevented in a mutant carrying an uncleaved propeptide. Although substrates of the caspase-like sites allosterically inhibit the chymotrypsin-like activity, inhibitors of the caspase-like sites do not affect the chymotrypsin-like sites. Furthermore, when caspase-like sites were occupied by the uncleaved propeptide or inhibitor, their substrates still inhibited the chymotrypsin-like activity. Thus, occupancy of the caspase-like sites stimulates the trypsin-like activity of proteasomes, but substrates of the caspase-like sites inhibit the chymotrypsin-like activity by binding to a distinct noncatalytic site.
  • Is Part Of: The Journal of biological chemistry, 19 September 2003, Vol.278(38), pp.35869-77
  • Identifier: ISSN: 0021-9258 ; PMID: 12815064 Version:1
  • Subjects: Non-Programmatic ; Caspases -- Chemistry ; Cysteine Endopeptidases -- Chemistry ; Multienzyme Complexes -- Chemistry
  • Language: English
  • Source: MEDLINE/PubMed (U.S. National Library of Medicine)

Searching Remote Databases, Please Wait