title: Covalent modification of the active site threonine of proteasomal beta subunits and the Escherichia coli homolog HslV by a new class of inhibitors.
abstract: The proteasome is a multicatalytic protease complex that plays a key role in diverse cellular functions. The peptide vinyl sulfone, carboxybenzyl-leucyl-leucyl-leucine vinyl sulfone (Z-L3VS) covalently inhibits the trypsin-like, chymotrypsin-like and, unlike lactacystin, also the peptidylglutamyl peptidase activity in isolated proteasomes, and blocks their function in living cells. Although described as a class of mechanism-based inhibitors for cysteine proteases, the peptide vinyl sulfone Z-L3VS and a 125I-labeled nitrophenol derivative (125I-NIP-L3VS) covalently modify the active site threonine of the catalytic beta subunits of the proteasome. Modification of Thermoplasma proteasomes demonstrates the requirement for a hydroxyl amino acid (threonine, serine) as nucleophile at the beta subunit's NH2 terminus. 125I-NIP-L3VS covalently modifies the HslV subunit of the Escherichia coli protease complex HslV/HslU, a reaction that requires ATP, and supports a catalytic mechanism shared with that of the eukaryotic proteasome.
authors.affiliation: Center for Cancer Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. boge@mit.edu
authors.forename: M
authors.initials: M
authors.lastname: Bogyo
authors.forename: J S
authors.initials: JS
authors.lastname: McMaster
authors.forename: M
authors.initials: M
authors.lastname: Gaczynska
authors.forename: D
authors.initials: D
authors.lastname: Tortorella
authors.forename: A L
authors.initials: AL
authors.lastname: Goldberg
authors.forename: H
authors.initials: H
authors.lastname: Ploegh
mesh_terms: D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D010450:Endopeptidases / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004926:Escherichia coli / Q000201:enzymology*; D006360:Heat-Shock Proteins; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*; D046988:Proteasome Endopeptidase Complex; D012697:Serine Endopeptidases; D013450:Sulfones / Q000494:pharmacology*; D013822:Thermoplasma / Q000201:enzymology*; D013912:Threonine / Q000737:chemistry / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; D009097:Multienzyme Complexes; D009842:Oligopeptides; D013450:Sulfones; C106727:carboxybenzyl-leucyl-leucyl-leucine vinyl sulfone; D013912:Threonine; D000255:Adenosine Triphosphate; D010450:Endopeptidases; D049069:ATP-Dependent Proteases; D012697:Serine Endopeptidases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D000251:Adenosine Triphosphatases