Figure 6.

Destabilizing interactions of zwitterionic detergent molecules with BM2 protein during dehydration. (Upper) The change in conformation of the BM2-DDM complex at ∼0.62 μs (see Fig. 5) correlates with extraction of a water molecule (green and white) from the central pore, mediated by interactions with the headgroup of a DHPC molecule. The water and DHPC molecule are shown in spacefilling format, and the protein (yellow) in cartoon format. (Lower) Destabilizing interactions of DPC detergent molecules similar to those depicted above, with the C terminus of BM2 are observed, in which a single detergent molecule gradually becomes lodged between two of the transmembrane helices, interacting with water molecules and remaining within the pore for the duration of the simulation. Water molecules within 4 Å of this His²⁷ residue are shown as a green surface.