Abstract
The aspartate-specific caspases are critical protease effecters 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 Å 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 P-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 caspases.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2031-2039 |
| Number of pages | 9 |
| Journal | EMBO Journal |
| Volume | 18 |
| Issue number | 8 |
| State | Published - Apr 15 1999 |
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Keywords
- Apoptosis
- Baculovirus
- Caspase inhibitor
- Crystallography
- P35
ASJC Scopus subject areas
- Genetics
- Cell Biology
Cite this
Crystal structure of baculovirus P35 : Role of a novel reactive site loop in apoptotic caspase inhibition. / Fisher, Andrew J; Dela Cruz, Wilfred; Zoog, Stephen J.; Schneider, Christine L.; Friesen, Paul D.
In: EMBO Journal, Vol. 18, No. 8, 15.04.1999, p. 2031-2039.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Crystal structure of baculovirus P35
T2 - Role of a novel reactive site loop in apoptotic caspase inhibition
AU - Fisher, Andrew J
AU - Dela Cruz, Wilfred
AU - Zoog, Stephen J.
AU - Schneider, Christine L.
AU - Friesen, Paul D.
PY - 1999/4/15
Y1 - 1999/4/15
N2 - The aspartate-specific caspases are critical protease effecters 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 Å 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 P-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 caspases.
AB - The aspartate-specific caspases are critical protease effecters 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 Å 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 P-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 caspases.
KW - Apoptosis
KW - Baculovirus
KW - Caspase inhibitor
KW - Crystallography
KW - P35
UR - http://www.scopus.com/inward/record.url?scp=0345654358&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0345654358&partnerID=8YFLogxK
M3 - Article
C2 - 10205157
AN - SCOPUS:0345654358
VL - 18
SP - 2031
EP - 2039
JO - EMBO Journal
JF - EMBO Journal
SN - 0261-4189
IS - 8
ER -