1I4E

CRYSTAL STRUCTURE OF THE CASPASE-8/P35 COMPLEX


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.236 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Covalent inhibition revealed by the crystal structure of the caspase-8/p35 complex.

Xu, G.Cirilli, M.Huang, Y.Rich, R.L.Myszka, D.G.Wu, H.

(2001) Nature 410: 494-497

  • DOI: 10.1038/35068604

  • PubMed Abstract: 
  • Apoptosis is a highly regulated process that is crucial for normal development and homeostasis of multicellular organisms. The p35 protein from baculoviruses effectively prevents apoptosis by its broad-spectrum caspase inhibition. Here we report the ...

    Apoptosis is a highly regulated process that is crucial for normal development and homeostasis of multicellular organisms. The p35 protein from baculoviruses effectively prevents apoptosis by its broad-spectrum caspase inhibition. Here we report the crystal structure of p35 in complex with human caspase-8 at 3.0 A resolution, and biochemical and mutagenesis studies based on the structural information. The structure reveals that the caspase is inhibited in the active site through a covalent thioester linkage to p35, which we confirmed by gel electrophoresis, hydroxylamine treatment and mass spectrometry experiments. The p35 protein undergoes dramatic conformational changes on cleavage by the caspase. The repositioning of the amino terminus of p35 into the active site of the caspase eliminates solvent accessibility of the catalytic dyad. This may be crucial for preventing hydrolysis of the thioester intermediate, which is supported by the abrogation of inhibitory activity through mutations at the N terminus of p35. The p35 protein also makes conserved contacts with the caspase outside the active-site region, providing the molecular basis for the broad-spectrum inhibitory activity of this protein. We demonstrate a new molecular mechanism of caspase inhibition, as well as protease inhibition in general.


    Organizational Affiliation

    Department of Biochemistry, Weill Medical College of Cornell University, New York, New York, 10021 USA




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Early 35 kDa protein
A
299Autographa californica nuclear polyhedrosis virusGene Names: P35
Find proteins for P08160 (Autographa californica nuclear polyhedrosis virus)
Go to UniProtKB:  P08160
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Caspase-8
B
258Homo sapiensGene Names: CASP8 (MCH5)
EC: 3.4.22.61
Find proteins for Q14790 (Homo sapiens)
Go to Gene View: CASP8
Go to UniProtKB:  Q14790
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
ACE
Query on ACE
A
NON-POLYMERC2 H4 O

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Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.236 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 99.970α = 90.00
b = 117.340β = 90.00
c = 346.450γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
GLRFphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-03-28
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2013-09-25
    Type: Derived calculations