Selected stereoprojections of the self-rotation function for Q-crystal diffraction. The chosen κ angle maps reveal the major peak (see arrows) at ω = 94.0°, ϕ = 88.4°, κ = 66.1°. Note that this peak lies between sixfold and fivefold symmetries (60 and 72°, respectively), but is far removed from sevenfold symmetry (51.4°). The axis corresponds to a pseudo-sixfold symmetry axis in the new hexamer ring structure found by molecular replacement, the details of which will be published elsewhere (Sysoeva et al., 2013 ▶). Calculations were made using POLARRFN from the CCP4 suite (Winn et al., 2011 ▶).