Figure 2.

Cyanobacterial CCRPs assemble into diverse filament-like structures in vitro. Bright field and epifluorescence micrographs of filament-like structures formed by purified and renatured Fm7001-His₆ (0.7 mg ml⁻¹), Slr7083-His₆ (1 mg ml⁻¹), All4981-His₆ (0.5 mg ml⁻¹), Syc2039-GFP-His₆ (0.3 mg ml⁻¹), HmpF_Syc-His₆ (0.5 mg ml⁻¹) and HmpF_Syn-His₆ (0.5 mg ml⁻¹). Proteins were dialyzed into 2 mM Tris-HCl, 4.5 M urea pH 7.5 (Fm7001), HLB (Slr7083), PLB (All4981, HmpF_Syc, HmpF_Syn) or BG11 (Syc2039). Renatured proteins were either directly analyzed by bright field microscopy (Fm7001) or stained with an excess of NHS-Fluorescein and analyzed by epifluorescence microscopy. The NHS-Fluorescein dye binds primary amines and is thus incompatible with urea, which is why Fm7001 filament-like structures were visualized by bright field microscopy. Scale bars: 10 µm or (Fm7001 inlay and Slr7083) 20 µm.