Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 71.19 kDa 
• Atom Count: 3900 
• Residue Count: 471 
• Unique protein chains: 1

3R5K

A designed redox-controlled caspase-7

• DOI: 10.2210/pdb3R5K/pdb

• Classification: HYDROLASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2011-03-18 Released: 2011-06-29 
• Deposition Author(s): Witkowski, W.A., Hardy, J.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.86 Å
• R-Value Free: 0.251 
• R-Value Work: 0.188 
• R-Value Observed: 0.191 

Literature

A designed redox-controlled caspase.

Witkowski, W.A., Hardy, J.A.

(2011) Protein Sci 20: 1421-1431

• PubMed: 21674661 
• DOI: 10.1002/pro.673
• Primary Citation of Related Structures:  
  3R5K


• PubMed Abstract: 
  

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 Å 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.

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Organizational Affiliation: 

Department of Chemistry, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Caspase-7	A, B	312	Homo sapiens	Mutation(s): 2  Gene Names: CASP7, MCH3 EC: 3.4.22.60
Find proteins for P55210 (Homo sapiens) Explore P55210  Go to UniProtKB:  P55210
NIH Common Fund Data Resources
PHAROS:  P55210 GTEx:  ENSG00000165806

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
FMT	A, B	FORMIC ACID C H2 O2 BDAGIHXWWSANSR-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.86 Å
• R-Value Free: 0.251 
• R-Value Work: 0.188 
• R-Value Observed: 0.191 
• Space Group: P 3₂ 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 89.85	α = 90
b = 89.85	β = 90
c = 185.91	γ = 120

Software Package:

Software Name	Purpose
ADSC	data collection
PHASER	phasing
REFMAC	refinement
XDS	data reduction
SCALA	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2011-03-18 
• Released Date: 2011-06-29 
Deposition Author(s): Witkowski, W.A., Hardy, J.A.

Revision History 

• Version 1.0: 2011-06-29
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2012-11-28
  Changes: Database references