Figure 3
Electron density map of PM projected onto a membrane plane. It was calculated with the diffraction amplitudes up to the (11 3) reflection, a resolution of 4.2 Å. The envelope shown by the dashed line shows the border of one BR monomer, and the characters A–G are the names of seven transmembrane α-helices. The triangle symbols denote the positions of threefold-rotational symmetry points. The arrow indicates a density peak that appears in the region surrounded by helices C, D, E and F (see results). |