Figure 5
2Fo − Fc electron-density maps of PC. (a) PC trimer composed of two subunits, α (blue) and β (green), (b) an α-helix and loop from the α subunit contoured at 2.0σ, (c) α-helices from both subunits at 1.5σ and (d) the chromophore of PC at 1.5σ |