2.2. Crystallization and derivatization  

DynU16 was concentrated to 15 mg ml⁻¹ using an Amicon Ultra-15 centrifugal filter (Merck KGaA, Darmstadt, Germany) and subjected to high-throughput crystallization screening, which was performed using a Mosquito LCP robot (SPT Labtech) with the commercially available screens NeXtal JCSG Core Suites I–IV. Crystals were observed in well B13 of Core Suite III (Table 2 ▸, Supplementary Fig. S1). The crystals were cryoprotected with 20% glycerol and flash-cooled in liquid nitrogen. A heavy-atom derivative was produced by soaking crystals in 1 M potassium iodide for 1.5 min prior to cryoprotection with 10% glycerol and flash-cooling.