Fig. 2. Design, structure and heme binding of four stranded β-sheet peptides. (A) Design of peptides 2–7 with the His residues involved in heme ligation shown in red. X9 denotes Gly, βAla, δAva, εAca, ζAha and ηAoa in peptides 2, 3, 4, 5, 6 and 7, respectively. (B) Heme binding isotherms of peptides 3 (blue), 4 (purple), 5 (orange), 6 (green) and 7 (red). (C) Section of two-dimensional 1H–1H NOESY spectrum showing NOE connectivity between amide protons. Long range NOEs are underlined and boldfaced. (D) Superimposed twenty lowest energy structures of peptide-7. (E) A selected structure of peptide-7 showing side chain packing within β-sheets. (F) Model structure of a heme–peptide-7 complex. The side chains of the two axial ligands coordinating heme are shown (purple). Residues localized at the micelle/water interface (cyan) and residues localized in the hydrophobic core of micelles (green) are highlighted.
