Fig. 2
Cryo-EM map of P-glycoprotein derived from the highest resolution 3D class. a Orthogonal views of the map and different regions of the map are coloured according to their interpretation: Grey mesh – regions equivalent to the existing structures and within 2 Å of the fitted model (4ksb after MDFF); Turquoise – detergent micelle and unassigned density; Yellow – N-terminal extension (background/left); Green – putative ADP molecules; Purple and Blue – inner features associated with drug binding (mostly obscured in this panel) . The map is displayed at a threshold enclosing a volume of 75 × 103 Å3 for the core regions (grey mesh) and 85 × 103 Å3 for features not accounted for by the fitted model. b Core regions of the map with the MDFF-refined model shown as red and orange ribbon representations (N- and C-terminal halves of the protein, respectively). c Shows the extracellular portions of the map, with density lacking for 2 residues (N90, M91, arrows). d Shows part of NBD1. Individual β-strands viewed end-on cannot be resolved whilst individual α-helices in different orientations can be identified