Fig. 3.

A₀ coordination and unmodeled density in the A₁ site. A shows the GsbRC model within its corresponding cryo-EM map at 2.5σ where a phosphatidylglycerol molecule (cyan) is fit into the nearby unmodeled density. The density corresponding to an unmodeled water that provides axial ligation to the central Mg of A₀ and the location of PscA-Arg638 that provides a counter ion to the phosphatidylglycerol headgroup are labeled. B shows the unmodeled density near A₀/A₁ fit with a phosphatidylglycerol where the map is shown at four contour levels