2cno

Crystal structures of caspase-3 in complex with aza-peptide epoxide inhibitors.

spinqualitylabelsall models 2cno, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2cno is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.95Å Ligands: M60 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CASP3_HUMAN Involved in the activation cascade of caspases responsible for apoptosis execution. At the onset of apoptosis it proteolytically cleaves poly(ADP-ribose) polymerase (PARP) at a '216-Asp-|-Gly-217' bond. Cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain. Cleaves and activates caspase-6, -7 and -9. Involved in the cleavage of huntingtin. Triggers cell adhesion in sympathetic neurons through RET cleavage. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Caspase-3 is a prototypic executioner caspase that plays a central role in apoptosis. Aza-peptide epoxides are a novel class of irreversible inhibitors that are highly specific for clan CD cysteine proteases. The five crystal structures of caspase-3-aza-peptide epoxide inhibitor complexes reported here reveal the structural basis for the mechanism of inhibition and the specificities at the S1' and the S4 subsites. Unlike the clan CA cysteine proteases, the catalytic histidine in caspase-3 plays a critical role during protonation and subsequent ring opening of the epoxide moiety and facilitates the nucleophilic attack by the active site cysteine. The nucleophilic attack takes place on the C3 carbon atom of the epoxide and results in an irreversible alkylation of the active site cysteine residue. A favorable network of hydrogen bonds involving the oxyanion hole, catalytic histidine, and the atoms in the prime site of the inhibitor enhance the binding affinity and specificity of the aza-peptide epoxide inhibitors toward caspase-3. The studies also reveal that subtle movements of the N-terminal loop of the beta-subunit occur when the P4 Asp is replaced by a P4 Ile, whereas the N-terminal loop and the safety catch Asp179 are completely disordered when the P4 Asp is replaced by P4 Cbz group. Exploring the S4 and S1 prime subsite specificities in caspase-3 with aza-peptide epoxide inhibitors.,Ganesan R, Jelakovic S, Campbell AJ, Li ZZ, Asgian JL, Powers JC, Grutter MG Biochemistry. 2006 Aug 1;45(30):9059-67. PMID:16866351 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Caspase 3D structures

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