Shutting off the "Kill Switch"

The Jmol image is based on pdb file 1I30

Backbone image of the Caspase 3/XIAP complex (2 complexes)

Interaction of Caspase Units B with the BirA subunits highlighting the hydrophobic pockets(shades of yellow) and hydrogen bonds(off-red) and acidic pocket (red)

Backbone image of a single Caspase3/XIAP complex

Hydrophobic cluster interaction between XIAP and Caspase

Second Major Interaction Site... The Sinker (yellow)

Critical Hbonds(light pink) and Salt Bridge(magenta) from Asp148(red) locking down IAP into cleft

Zinc Coordinating Cysteine

Caspase substrate binding cleft (orange interior) with important active site His237(sky blue)

Modeling the Caspase3/XIAP Complex

XIAP

• The hook of the BIR2 domain is colored khaki
  
• The line of the BIR2 domain is colored light green
  
• The sinker of the BIR2 domain is colored light blue
  
• The globular domain of BIR2 is colored plum
  
• The sidechains are displayed in CPK and represent the hydrophobic clusters that interact with caspase 3
  
• The globular domain of BIR2 contains a zinc finger. The zinc atom is coordinated by three cysteines and one histidine, displayed in ball and stick and colored CPK
  
• The backbone of cysteine 203 is colored a darker shade of purple. This is the cysteine is changed to a tyrosine in Nic Volker.
  

Caspase-3

• The active site (tyrosine) is colored red
  
• The sidechains are displayed in CPK and represent the hydrophobic clusters that interact with caspase3