Figure 4.

Phase diagrams for FutA and UbiX. The raw plots for Prochlorococcus MED4 FutA and P. aeruginosa UbiX are shown in panels (a) and (b), respectively. The plots are based on two vapour diffusion crystallization experiments, with and without protein crystal seeds (see Section 4.1). The size of each circle corresponds to the approximate number of crystals observed in the crystallization drop. The opaque and shadowed circles show the number of crystals present from drops with no seeds and seeds, respectively. The red lines refer to the approximate boundaries between the different zones of the diagram. (c), (d) Representations of the plots shown in panels (a) and (b), respectively: darker shading indicates regions of higher nucleation, grey hatching shows drops where precipitation was visible, and the pink shading in the UbiX plot [panel (d)] highlights the region where a tetragonal crystal form appears. The crystallization drop images in panel (c) show the different levels of nucleation observed in both the seeded and un-seeded conditions. The images in panel (d) show the two different crystal forms of UbiX. The red and blue scale bars in the images denote 600 and 300 µm, respectively.