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. 2020 Oct 22;9:e58593. doi: 10.7554/eLife.58593

Figure 1. The NavMs sodium channel-cannabidiol (CBD) crystal structure.

Figure 1.

(A) The crystal structure (2.3 Å resolution) of the NavMs sodium channel (in coral coloured ribbon depiction) with one CBD molecule (in green space-filing depiction), showing its location within the hydrophobic cavity of the channel, located adjacent to the fenestration. Three sodium ions are shown as grey spheres in the selectivity filter, for visual reference. The view on the right is rotated 90 degrees from the view on the left. (B) As in (A) but showing 4 CBD molecules in stick depiction. (C) (left) Surface view of space filling structure of NavMs coloured by electrostatics with CBD (in green) present. The orientation is the same as in the left panel of part A. The CBD (in green) is only just visible through the exterior end of one of the fenestration holes. (right) As in panel B, but with a slice through the space filling model (and through the middle of the fenestrations). For clarity only 2 CBD molecules are included, showing where the drug lies along the fenestration and blocks the ion pathway. (D) The CBD-binding site: the polypeptide backbone of the NavMs-CBD complex is depicted in ribbon motif. The ribbons are coloured by subunit (regions of the subunits that come in close contact with the one CBD molecule shown, are depicted in red, grey, blue, and yellow). The (2Fo-Fc) map (in blue mesh) was calculated at 0.7 sigma and the structure of the CBD molecule present is in stick depiction. (E) Detailed views of the residues that lie within 3.9 Å of the CBD molecule (which is depicted in green/red stick representation) are shown and coloured by domain (as in part D). The H-bond between CBD and NavMs involves the M175 backbone carbonyl group, which is shown as a dashed black line. The distance between the side chain of T207 and the CBD molecule is 3.7 Å, and is indicated by a dotted red line. This is the residue that was mutated in the electrophysiology studies. The pink sphere indicates the sodium ion site in the selectivity filter which is furthest from the extra-membranous surface (the one located farthest into the channel). On the right is the same view, rotated by 90 degrees.