Figure 4.

Axial view of the predicted structure of the M₂ proton channel. The individual panels show successive slices (≈5 Å) through the structure. The residues that appear essential from mutagenic analysis—Val-27 (A), Ala-30 and Ser-31 (B), Gly-34 (C), His-37 (D), and Trp-41 (E)—-are shown as ball-and-stick representations. The dotted surface shows the parts of the model accessible to a probe with a 1.4-Å radius. Color designation: blue, Val-27, Ala-30, Gly-34, His-37, and Trp-41; red, Ser-31; gray, all other residues. This figure was generated using insightii.