Figure 1.

P4₃ data analysis and final model. (a) Twinning analysis using the L-test performed with the Merohedral Crystal Twinning Server: Padilla–Yeates Algorithm (Padilla & Yeates, 2003 ▶) shows almost perfect twinning. The curve for the observed data (blue) more closely resembles the curve for theoretically perfectly twinned data (red curve) than that for theoretically untwinned data (red line). The twin fraction related by the twin law h, −k, −l was estimated at 0.45. (b) The self-rotation function plot at κ = 180 shows two noncrystallographic rotational symmetry axes labelled 1 and 2. Peaks corresponding to crystallographic twofold axes for this space group are labelled C. Despite the presence of higher rotational symmetry, assignment of a higher symmetry space group to the data resulted in over-merging. (c) The final model contained four copies in the asymmetric unit, each in unique orientations related by two twofold rotational axes. (d) Representative density from a 2F _o − F _c σ_A-weighted map calculated in Phenix is shown for the final model.