Figure 1. Sequence Composition and Anti-apoptotic Binding Activity of Hydrocarbon-stapled PUMA BH3 Peptides.
(A, B) A series of FITC-PUMA SAHBA peptides of differential BH3 domain length (A) and FITC-PUMA BH3 (131–153) constructs with varying staple positions (as reflected by the “staple walk” along the pictured helical wheel) (B) were synthesized and screened for BCL-XLΔC binding activity by fluorescence polarization assay. See also Figure S1B for separated views of the PUMA SAHB A1-L1 plots.
(C) Circular dichroism of PUMA SAHBA1 and its A139L/L141A mutant demonstrated the marked α-helical structure of both stapled peptides in aqueous solution. *, exceeds the calculated ideal α-helicity of an undecapeptide standard.
(D) FITC-PUMA SAHBA1 (solid lines) exhibits high affinity binding to the diversity of anti-apoptotic BCL-2 family proteins, whereas A139L/L141A point mutagenesis (dashed lines) markedly impairs binding activity, highlighting the BH3 sequence-dependence of PUMA SAHBA1 engagement. Data are mean ± S.D. for experiments performed in triplicate. X, stapling amino acid; B, norleucine.
See also Figure S1.