Fig. 2.

Active site region of NmEptA. (A) Amphipathic helices PH2 and PH2′, with the polar residues shown in dark green and nonpolar residues shown in pale green. (B) Difference electron density contoured at 3 σ, with a model of DDM included in the density. (C) Ribbon representation of NmEptA showing the tunnel (green) in the structure, as calculated by CAVER. The Zn²⁺ ion is represented as an orange sphere. In B and C, the TM domain is colored as a red ribbon representation, and the soluble domain is colored as a blue ribbon representation. The active site residues are shown as ball and stick representation colored with white bonds, and the DDM molecule is colored with yellow bonds. The membrane surface is shown by a black line in each panel.