Experimental Data Snapshot

  • Resolution: 2.20 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 

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This is version 1.2 of the entry. See complete history


Crystal structure of baculovirus P35: role of a novel reactive site loop in apoptotic caspase inhibition.

Fisher, A.J.Cruz, W.Zoog, S.J.Schneider, C.L.Friesen, P.D.

(1999) EMBO J 18: 2031-2039

  • DOI: https://doi.org/10.1093/emboj/18.8.2031
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The aspartate-specific caspases are critical protease effectors of programmed cell death and consequently represent important targets for apoptotic intervention. Baculovirus P35 is a potent substrate inhibitor of metazoan caspases, a property that accounts for its unique effectiveness in preventing apoptosis in phylogenetically diverse organisms. Here we report the 2.2 A resolution crystal structure of P35, the first structure of a protein inhibitor of the death caspases. The P35 monomer possesses a solvent-exposed loop that projects from the protein's main beta-sheet core and positions the requisite aspartate cleavage site at the loop's apex. Distortion or destabilization of this reactive site loop by site-directed mutagenesis converted P35 to an efficient substrate which, unlike wild-type P35, failed to interact stably with the target caspase or block protease activity. Thus, cleavage alone is insufficient for caspase inhibition. These data are consistent with a new model wherein the P35 reactive site loop participates in a unique multi-step mechanism in which the spatial orientation of the loop with respect to the P35 core determines post-cleavage association and stoichiometric inhibition of target caspases.

  • Organizational Affiliation

    Department of Chemistry and Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA. fisher@chem.ucdavis.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C
299Autographa californica nucleopolyhedrovirusMutation(s): 0 
Gene Names: P35
Find proteins for P08160 (Autographa californica nuclear polyhedrosis virus)
Explore P08160 
Go to UniProtKB:  P08160
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08160
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.20 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.196 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 114.58α = 90
b = 130.11β = 90
c = 181.08γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-06-01
    Type: Initial release
  • Version 1.1: 2008-03-03
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance