4bpk
From Proteopedia
Bcl-xL bound to alpha beta Puma BH3 peptide 5
Structural highlights
Function[B2CL1_HUMAN] Potent inhibitor of cell death. Inhibits activation of caspases (By similarity). Appears to regulate cell death by blocking the voltage-dependent anion channel (VDAC) by binding to it and preventing the release of the caspase activator, CYC1, from the mitochondrial membrane. Also acts as a regulator of G2 checkpoint and progression to cytokinesis during mitosis.[1] [2] Isoform Bcl-X(S) promotes apoptosis.[3] [4] Publication Abstract from PubMedWe have used computational methods to improve the affinity of a foldamer ligand for its target protein. The effort began with a previously reported alpha/beta-peptide based on the BH3 domain of the proapoptotic protein Puma; this foldamer binds tightly to Bcl-x(L) but weakly to Mcl-1. The crystal structure of the Puma-derived alpha/beta-peptide complexed to Bcl-x(L) was used as the basis for computational design of variants intended to display improved binding to Mcl-1. Molecular modelling suggested modification of three alpha residues of the original alpha/beta backbone. Individually, each substitution caused only a modest (4- to 15-fold) gain in affinity; however, together the three substitutions led to a 250-fold increase in binding to Mcl-1. These modifications had very little effect on affinity for Bcl-x(L). Crystal structures of a number of the new alpha/beta-peptides bound to either Mcl-1 or Bcl-x(L) validated the selection of each substitution. Overall, our findings demonstrate that structure-guided rational design can be used to improve affinity and alter partner selectivity of peptidic ligands with unnatural backbones that bind to specific protein partners. Structure-guided rational design of alpha/beta-peptide foldamers with high affinity for BCL-2 family prosurvival proteins.,Smith BJ, Lee EF, Checco JW, Evangelista M, Gellman SH, Fairlie WD Chembiochem. 2013 Sep 2;14(13):1564-72. doi: 10.1002/cbic.201300351. Epub 2013, Aug 8. PMID:23929624[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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