JBScreen Classic 3 (PEG 4000 + based)

The JBScreen Crystal Screening Kits 1-10 cover 240 of the most prominent buffers for protein crystallization. Their compositions result from data mining of several thousands of crystallized proteins. JBScreen represents the statistically most successful buffers that yielded protein crystals suitable for X-ray diffraction. The JBScreen buffers are principally ordered by type and concentration of the precipitant. This allows easy extraction of all relevant information and is already a first step to a refinement: Once you get a hit, you immediately see the effects of the neighbouring conditions. Subsequent fine tuning of preliminary hits will be much more efficient. Apart from saving you the tedious pipetting, sterile packed aliquots have several other important advantages: While common bulk solutions are frequently contaminated by the time you use the first aliquot, JBScreen is alalways fresh and sterile. Evaporation of solvent (with the resulting change of the buffer) just won’t happen – you will get extremely reproducible screening results.

The kit contains the following buffers:
A1 8% PEG 4000, 0.8 M Li Chloride, 0.1 M TRIS HCl pH 8.5
A2 10% PEG 4000, 20% iso-Propanol
A3 10% PEG 4000, 10% iso-Propanol, 0.1 M Na Citrate pH 5.6
A4 10% PEG 4000, 5% iso-Propanol, 0.1 M Na HEPES pH 7.5
A5 10% PEG 4000, 20% iso-Propanol, 0.1 M Na HEPES pH 7.5
A6 12% PEG 4000, 0.1 M Na Acetate pH 4.6, 0.2 M Ammonium Sulfate
B1 15% PEG 4000, 0.2 M Ammonium Sulfate
B2 15% PEG 4000, 0.1 M Na Citrate pH 5.6, 0.2 M Ammonium Sulfate
B3 16% PEG 4000, 10% iso-Propanol, 0.1 M Na HEPES pH 7.5, 0.2 M Ammonium Sulfate
B4 20% PEG 4000, 0.2 M Ammonium Sulfate
B5 20% PEG 4000, 10% Glycerol, 0.2 M Mg Sulfate
B6 20% PEG 4000, 5% iso-Propanol, 0.1 M Na Citrate
C1 20% PEG 4000, 20% iso-Propanol, 0.1 M Na Citrate
C2 20% PEG 4000, 0.6 M Na Chloride, 0.1 M Na MES pH 6.5
C3 20% PEG 4000, 10% iso-Propanol, 0.1 M Na HEPES pH 7.5
C4 22% PEG 4000, 0.2 M Ammonium Sulfate, 0.1 M Na Acetate
C5 25% PEG 4000, 0.1 M Na Acetate pH 4.6, 0.2 M Ammonium Sulfate
C6 25% PEG 4000, 0.1 M Na Citrate pH 5.6, 0.2 M Ammonium Sulfate
D1 25% PEG 4000, 0.1 M Na HEPES pH 7.5, 0.2 M Li Sulfate, 0.1 M Na Acetate
D2 25% PEG 4000, 8% iso-Propanol, 0.1 M Na Acetate
D3 30% PEG 4000, 0.2 M Ammonium Sulfate
D4 30% PEG 4000, 0.1 M Na Acetate pH 4.6, 0.2 M Ammonium Sulfate
D5 30% PEG 4000, 0.1 M Na Citrate pH 5.6, 0.2 M Ammonium Sulfate
D6 32% PEG 4000, 0.8 M Li Chloride 0.1 M TRIS HCl pH 8.5

Buffer preparation:
• Chemicals used were of MicroSelect grade for Molecular Biology.
• Buffers were prepared as 1 M stock solutions. The pH was adjusted with HCl (Imidazole, TRIS), NaOH (Bicine, CHES, HEPES, MES), Citric Acid (Citrate) or Acetic Acid (Acetate) (23°C; Fisher pH electrode).
• Percentages given are always w/v values (for solids as well as for liquids).
• The final volume was adjusted with >18 MOhm water.
• Solutions were filtered (0.2 µm) and filled in ampoules/tubes under sterile conditions.