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. Author manuscript; available in PMC: 2013 Oct 1.
Published in final edited form as: Biopolymers. 2012;98(5):451–465. doi: 10.1002/bip.22080

Figure 2.

Figure 2

Properties of native and Aib-stabilized peptides. (A) Sequences of the α5 region of XIAP-BIR3 (BIR3) and peptides 1–9. * represents aminoisobutyric acid (Aib). (B) CD spectra of the native Peptide 5 and the Aib-stabilized Peptide 8 demonstrate that the presence of Aib increases the helicity of the peptides. (C) Native and Aib-stabilized peptides (1–9) show some inhibition of full-length caspase-9 (C9 FL) or the N-terminal CARD-domain deleted caspase-9 (C9 ΔN) to cleave a natural caspase-9 substrate, the caspase-7 zymogen (C7 C186A) to the caspase-7 large (C7 Lg) and small (C7 Sm) subunits in an in vitro cleavage assay monitored by gel mobility. B; Purified BIR3. (D) Peptide 2 (MW 3118) is chemically stable even after a 3-week, 4°C incubation. (E) Aged Peptide 2 but not freshly rehydrated Peptide 2 inhibits caspase-9. (F) 3-week aged Peptide 2 non-specifically activates both caspase-9 and caspase-7 in a manner similar to the polymeric crowding agent PEG 8,000.