Lipid Exchange Mechanism of the Cholesteryl Ester Transfer Protein Clarified by Atomistic and Coarse-grained Simulations
Figure 6
Hypothesis for the initial event of helix X assisted core lipid exchange.
A) Two RMSD-fitted snapshots from the simulation A3-90POPC showing the rearrangement of helix X (darkened colour). The green conformation is for the open state and the blue one for the closed state. A more detailed structure of helix X and the role of the hinge region during the conformational change (red and transparent region) are shown in the lower snapshots. CEs are shown as orange sticks. The residues 462–476 and 193–202 of CETP have been rendered using sticks, and coloring is based on the polarity of residues. B) Spatial number density of POPCs (grey and transparent) and CEs (orange) during the simulation A3-90POPC. Core CEs diffuse into the hydrophobic tunnel of CETP (green spheres) without helix X. C) Number of contacts between core CEs and interior CE-473 when helix X is in the open state (black) or completely removed (red).