FIG 4.

NMR structure of the agnoprotein peptide in the presence of 30% TFE (vol/vol) at pH 3.0 and a temperature of 313 K calculated using ARIA (40) and CNS (41). (A) The NMR structure-based α-helical region and the Leu/Ile/Phe-rich domain of agnoprotein within the α-helix are indicated. (B) Superimposition of the 17 energetically most favorable structures of the peptide on the backbone atoms of the domain from K23 to F39 of the averaged structure. The α-helix and unstructured regions are in red and green, respectively. The structure is characterized by two unstructured regions from residues T17 to K22 and C40 to Q52, which are colored green. In some structures, a short α-helix from E43 to D47 is formed in the C-terminal domain. (C) Helical wheel representation of the α-helix (K23 to F39) of the agnoprotein peptide. Hydrophilic and hydrophobic residues are colored blue and red, respectively. The distribution of the residues on the two sides of the helix suggests amphipathic properties for this structure. The α-helical domain from residues K23 to F39 shows amphipathic properties: hydrophobic residues (I28, L29, I30, F31, L32, L33, F35, L36, L37, and F39) form a large surface of interaction, while hydrophilic charged residues (K23, E34, R27, and D38) form a very narrow surface.