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Global analysis of proteasomal substrate specificity using positional-scanning libraries of covalent inhibitors.
Nazif, T; Bogyo, M.
Affiliation
  • Nazif T; Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA.
Proc Natl Acad Sci U S A ; 98(6): 2967-72, 2001 Mar 13.
Article in En | MEDLINE | ID: mdl-11248015
The proteasome is a large protease complex consisting of multiple catalytic subunits that function simultaneously to digest protein substrates. This complexity has made deciphering the role each subunit plays in the generation of specific protein fragments difficult. Positional scanning libraries of peptide vinyl sulfones were generated in which the amino acid located directly at the site of hydrolysis (P1 residue) was held constant and sequences distal to that residue (P2, P3, and P4 positions) were varied across all natural amino acids (except cysteine and methionine). Binding information for each of the individual catalytic subunits was obtained for each library under a variety of different conditions. The resulting specificity profiles indicated that substrate positions distal to P1 are critical for directing substrates to active subunits in the complex. Furthermore, specificity profiles of IFN-gamma-regulated subunits closely matched those of their noninducible counterparts, suggesting that subunit swapping may modulate substrate processing by a mechanism that does require a change in the primary sequence specificity of individual catalytic subunits in the complex. Finally, specificity profiles were used to design specific inhibitors of a single active site in the complex. These reagents can be used to further establish the role of each subunit in substrate processing by the proteasome.
Subject(s)

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Cysteine Endopeptidases / Cysteine Proteinase Inhibitors / Peptide Library / Multienzyme Complexes Limits: Animals Language: En Journal: Proc Natl Acad Sci U S A Year: 2001 Document type: Article Affiliation country: United States Country of publication: United States

Full text: 1 Collection: 01-internacional Database: MEDLINE Main subject: Cysteine Endopeptidases / Cysteine Proteinase Inhibitors / Peptide Library / Multienzyme Complexes Limits: Animals Language: En Journal: Proc Natl Acad Sci U S A Year: 2001 Document type: Article Affiliation country: United States Country of publication: United States