JBScreen Classic 2 (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 4% PEG 4000, 0.1 M Na Acetate pH 4.6
A2 8% PEG 4000
A3 8% PEG 4000, 0.1 M Na Acetate pH 4.6
A4 10% PEG 4000, 0.1 M Na MES pH 6.5, 0.2 M Mg Chloride
A5 12% PEG 4000, 0.1 M Na HEPES pH 7.5, 0.1 M Na Acetate
A6 12% PEG 4000, 0.1 M TRIS HCl pH 8.5
B1 16% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Li Sulfate
B2 16% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Na Acetate
B3 16% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Mg Chloride
B4 18% PEG 4000, 0.1 M Na Acetate pH 4.6
B5 20% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Li Sulfate
B6 20% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Ca Chloride
C1 22% PEG 4000, 0.1 M Na HEPES pH 7.5, 0.1 M Na Acetate
C2 25% PEG 4000, 0.1 M Na Acetate pH 4.6
C3 25% PEG 4000, 0.1 M Na MES pH 6.5, 0.2 M Mg Chloride
C4 25% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Ca Chloride
C5 30% PEG 4000
C6 30% PEG 4000, 0.1 M Na Acetate pH 4.6, 0.1 M Mg Chloride
D1 30% PEG 4000, 0.1 M Na MES pH 6.5
D2 30% PEG 4000, 0.1 M Na HEPES pH 7.5, 0.2 M Ca Chloride
D3 30% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Li Sulfate
D4 30% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Na Acetate
D5 30% PEG 4000, 0.1 M TRIS HCl pH 8.5, 0.2 M Mg Chloride
D6 35% PEG 4000

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.