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Title: A designed redox-controlled caspase

Caspases are a powerful class of cysteine proteases. Introduction of activated caspases in healthy or cancerous cells results in induction of apoptotic cell death. In this study, we have designed and characterized a version of caspase-7 that can be inactivated under oxidizing extracellular conditions and then reactivated under reducing intracellular conditions. This version of caspase-7 is allosterically inactivated when two of the substrate-binding loops are locked together via an engineered disulfide. When this disulfide is reduced, the protein regains its full function. The inactive loop-locked version of caspase-7 can be readily observed by immunoblotting and mass spectrometry. The reduced and reactivated form of the enzyme observed crystallographically is the first caspase-7 structure in which the substrate-binding groove is properly ordered even in the absence of an active-site ligand. In the reactivated structure, the catalytic-dyad cysteine-histidine are positioned 3.5 {angstrom} apart in an orientation that is capable of supporting catalysis. This redox-controlled version of caspase-7 is particularly well suited for targeted cell death in concert with redox-triggered delivery vehicles.
Authors:
;  [1]
  1. (UMASS, Amherst)
Publication Date:
OSTI Identifier:
1025047
Resource Type:
Journal Article
Resource Relation:
Journal Name: Protein Sci.; Journal Volume: 20; Journal Issue: (8) ; 08, 2011
Research Org:
Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
Sponsoring Org:
NIH
Country of Publication:
United States
Language:
ENGLISH
Subject:
59 BASIC BIOLOGICAL SCIENCES; 60 APPLIED LIFE SCIENCES; APOPTOSIS; CATALYSIS; CELL KILLING; CYSTEINE; DISULFIDES; ENZYMES; INDUCTION; MASS SPECTROSCOPY; ORIENTATION; PROTEINS