Figure 3.
Fig. 3. Model for lipid-assisted conversion. Helices are
represented as cylinders and colored as in Fig. 1. Hydrophobic
residues are depicted as green sticks. The C-terminal domain is
shown as a C^ worm in an arbitrary
orientation and position as a single, long helix. (A) Initial
lipid-free conformation of apoA-I. Residues contributing to the
hydrophobic patch at the N terminus of helix 1 are shown. (B and
C) The two geometrically possible open conformations, formed
through lipid binding to the bundle. The energetically more
likely conformation (C) is indicated by a solid arrow.
Hydrophobic side chains that contribute to the four-helix bundle
interface are exposed. (D) Rearrangement of a fraction of the
open form into a stable helix-hairpin intermediate. Residues
forming the new hydrophobic stabilization core are illustrated.
(E) Putative conformation in the HDL-bound form, represented by
the 1-43 structure.
Hydrophobic residues that could potentially form the interaction
interface with lipid in HDL are shown.
worm in an arbitrary
orientation and position as a single, long helix. (A) Initial
lipid-free conformation of apoA-I. Residues contributing to the
hydrophobic patch at the N terminus of helix 1 are shown. (B and
C) The two geometrically possible open conformations, formed
through lipid binding to the bundle. The energetically more
likely conformation (C) is indicated by a solid arrow.
Hydrophobic side chains that contribute to the four-helix bundle
interface are exposed. (D) Rearrangement of a fraction of the
open form into a stable helix-hairpin intermediate. Residues
forming the new hydrophobic stabilization core are illustrated.
(E) Putative conformation in the HDL-bound form, represented by
the 
1-43 structure.
Hydrophobic residues that could potentially form the interaction
interface with lipid in HDL are shown.