Caspase-3 Regulatory Mechanisms: Difference between revisions
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Taking a closer look at L2 and L2’ we can see a critical interaction involving <scene name='Caspase-3_Regulatory_Mechanisms/D169_nospin/4'>Aspartate 169</scene> on L2. This residue makes two hydrogen bonds with backbone amides of V189’ and E190’, stabilizing L2 in the proper position. This reinforcement allows L2 to contact L3 so as to twist the active site cysteine into the proper orientation to attack the substrate. It also causes a conformational change at Tyrosine 203. The hydroxyl group occupies the P1 position in the active site, blocking substrate binding. However, when L2 contacts L2' and finds the proper orientation, Y203 rotates 90 degrees and leaves a hole for P1 of the substrate. In addition, L2 can now contact L4 at K260. This secures L4 and allows it to make contacts in the P4 position, which greatly influence substrate specificity. | Taking a closer look at L2 and L2’ we can see a critical interaction involving <scene name='Caspase-3_Regulatory_Mechanisms/D169_nospin/4'>Aspartate 169</scene> on L2. This residue makes two hydrogen bonds with backbone amides of V189’ and E190’, stabilizing L2 in the proper position. This reinforcement allows L2 to contact L3 so as to twist the active site cysteine into the proper orientation to attack the substrate. It also causes a conformational change at Tyrosine 203. The hydroxyl group occupies the P1 position in the active site, blocking substrate binding. However, when L2 contacts L2' and finds the proper orientation, Y203 rotates 90 degrees and leaves a hole for P1 of the substrate. In addition, L2 can now contact L4 at K260. This secures L4 and allows it to make contacts in the P4 position, which greatly influence substrate specificity. | ||
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=== Caspase-3 Active Site=== | === Caspase-3 Active Site=== | ||