Table 1:
A summary of crystallization conditions used in this work and a comparison of crystal size, morphology, density, and time to first crystals, obtained from on-chip crystallization and comparable crystallization in 24-well crystallization plates. For on-chip crystallization, ~8 μL of solution was loaded into the chip and the chip was stored either sealed (micro-batch) or unsealed (vapor diffusion) in an enclosed environment with the precipitant solution in the reservoir. Similar droplet volumes were used for crystallization in a 24-well plate format using micro-batch under oil (paraffin) or hanging drop vapor diffusion methods for comparison, as appropriate. Crystal density (n= # of crystals/mm2) was measured using optical microscopy and qualitatively described as low for n≤ 10, medium for 10 < n < 100, and high for n ≥ 100.
| Protein | Protein solution | Precipitant solution | Incubation Temperature | Crystallization method | Crystal size, morphology, density, crystallization time | |
|---|---|---|---|---|---|---|
| On-chip | 24-well Crystallization plate | |||||
|
| ||||||
| Lysozyme | 30 mg/mL in 20 mM Sodium Acetate buffer, pH 4.6 | 1M Sodium Chloride, 0.1M Sodium Acetate buffer, pH 4.6 | 4°C | Micro-batch | 25–35 μm, cuboid, high, ~2–3 hours. | 25–35 μm, cuboid, high, ~2–3 hours. |
| 50 mg/mL in DI water | 2M Sodium Chloride, 0.1M Sodium Acetate buffer, pH 4.6 | 21°C | Micro-batch | 60–100 μm, cuboid, low, 12–24 hours. | 30–70 μm, cuboid, medium, 2–4 hours. | |
|
| ||||||
| Thaumatin | 25 mg/ml in DI water | 1M L-Sodium Potassium Tartrate, 0.1M ADA buffer, pH 6.5 | 4°C | Micro-batch | ~25 μm, tetragonal bipyramidal, low, ~12 hours. Crystals grow to 70–100 μm in size over 2–3 days. | ~20 μm, tetragonal bipyramidal, high, ~12 hours. |
| 21°C | Micro-batch | 50–100 μm, tetragonal bipyramidal, low, 3–4 days. | Did not crystallize | |||
| 21°C | Vapor diffusion | 50–100 μm, tetragonal bipyramidal, low, ~24 hours. | 50–150 μm, tetragonal bipyramidal, low, ~24 hours. | |||
| 21°C | Micro-batch (with seeding using 1° seed stock 1:5:5 seed: protein: precipitant) | 15–20 μm, tetragonal bipyramidal, high, ~24 hours. | 15–20 μm, tetragonal bipyramidal, high, ~24 hours | |||
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| Concanavalin-A (Type VI) | 70 mg/mL in 20 mM Tris buffer, pH 8.0 | 2.8M Ammonium Sulfate in 0.1M Tris buffer, pH 8.5 | 21°C | Micro-batch | 150–300 μm, round base rhombic tetrahedron, low, ~12 hours. | 30–60 μm, cubic, high, 0–2 hours initially; equilibrates to 150–300 μm, round base rhombic tetrahedron, low, over the next 3–7 days. |
|
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| Bovine Liver Catalase | 40 mg/mL in 50 mM Sodium Phosphate buffer, pH 6.8 | 22.5% PEG 4000 in 0.1M Tris buffer, pH 8.5 | 21°C | Micro-batch | 70–120 μm, prism shaped, low, <12 hours | 70–120 μm, prism shaped, low, 2–4 hours |
| 21°C | Vapor diffusion | 30–100 μm, prism shaped, medium, 0–4 hours | 30–100 μm, prism shaped, medium, 0–2 hours | |||
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| NSP5 | 5mg/ml in 20 mM Tris pH 7.8, 150 mM NaCl, 0.5 mM TCEP, 1 mM EDTA | 100 mM Bis-Tris pH 6.5, 17.5% w/v PEG 3350, 175 mM; Li2SO4; 10% 1:100 2’ seeds | 21°C | Vapor diffusion, with seeding | 300 um, large thin plate clusters, low, ~12 hours | 150–200 μm large single plates or plate clusters, low, ~12 hours |