Fig. 3

Novel features of the cryo-EM map: a,b Sections through the transmembrane region. a Shows two additional high density features (purple) that sit just below the cyclic peptide inhibitor binding site (dashed circle) and mostly formed by transmembrane (TM) helices 10,11,12,4,5 & 6 (clipped away for clarity). b Residues surrounding the two central densities (purple mesh) in the MDFF atomic model viewed from the extracellular side. c Blue density continuous with the detergent micelle (turquoise) fills the gaps formed by the inverted ‘V’ of TM helices 3&4 (left) and 9&10 (right,TM helices 4 and 9 are clipped away for clarity). d Additional density (yellow) below the detergent micelle (turquoise) that extends to the start of the elbow helix (EH) beginning at V33 in the fitted model (4ksb). This wraps over the protruding TM6 that connects to NBD1. e,f Additional densities at the interfacial surfaces of NBD1 and NBD2 (green transparent surface). Density for the core regions is shown in grey mesh. In both panels elongated additional densities are located at the expected ADP/vanadate site (right hand side in both panels). Two further small densities (left side in each panel) lie close to the Signature region. MDFF-refined models with ADP (red, orange traces) and without ADP (pink, yellow) are shown with few systematic differences except for the MDFF-refined ADP (black, ball and stick representation). The Signature sequence, Walker A residues and the conserved catalytic glutamates in the Walker B regions are highlighted with stick representation. Red/pink traces represent the N-terminal half of the molecule; orange/yellow the C-terminal half