Skip to main content
. 2017 Jul 18;6:e26933. doi: 10.7554/eLife.26933

Figure 4. Comparison of intact WOC site and Mn-depleted site.

(A) Coordination of the intact WOC by side chains from the D1 subunit (cream) and CP43 (green) and four water molecules (W1–W4). Arg357(CP43) and His 337(D1) form hydrogen bonds to WOC oxygen atoms (Umena et al., 2011). (B) Model of sidechains and electron density map (1 sigma 2Fo-Fc, grey) of the apo-WOC and electron density (0.8–1.5 sigma 2Fo-Fc, blue) tentatively modeled as waters at the site of the WOC and surrounding water molecules (blue). Multiple contour lines indicate a stronger (more defined) peak in the electron density map (e.g. waters at Asp170), while fewer lines show a weaker signal (e.g. the water at the WOC O2 site). (C) Overlay of apo-WOC model (green) with two holo-PSII models at a similar (PDB: 4PJ0, [Hellmich et al., 2014], light grey) and higher resolution (PDB: 3WU2, [Umena et al., 2011], dark grey).

DOI: http://dx.doi.org/10.7554/eLife.26933.010

Figure 4.

Figure 4—figure supplement 1. Overlay of the WOC-coordinating side chains at both monomers of dPSIIcc.

Figure 4—figure supplement 1.

(A/B) Overlay of residues coordinating the WOC (thin lines) in two reference structures (4Pj0 Hellmich et al. and 3WU2 Umena et al.) with the same residues in apo-PSII (green). (C) The same residues in apo-PSII. Residues formerly coordinating Mn/Ca are shown in sand (D1) and green (CP43), those within hydrogen-bond distance to μ-oxo bridges in grey. 1 σ 2Fo-Fc map surrounding the side chains is shown as blue mesh. Position of the WOC in 3WU2 is indicated as thin black lines.
DOI: http://dx.doi.org/10.7554/eLife.26933.011
Figure 4—figure supplement 2. Stereo view of the WOC binding site as shown in Figure 4 but with the 0.8–1.5 σ 2Fo-Fc electron density map (blue) shown at water positions (blue spheres) and chloride positions (emerald spheres) only.

Figure 4—figure supplement 2.

Grey spheres indicate water positions in the high-resolution reference structure 3WU2.
DOI: http://dx.doi.org/10.7554/eLife.26933.012
Figure 4—figure supplement 3. Stereo view comparing water positions at the WOC site in apo-PSII (green) with those in 3WU2 (purple).

Figure 4—figure supplement 3.

Chloride ions are shown in emerald for apo-PSII only.
DOI: http://dx.doi.org/10.7554/eLife.26933.013