JBScreen Classic 7 (MPD 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 10% MPD, 0.1 M Na HEPES pH 7.5, 0.1 M Na Citrate
A2 12% MPD, 0.1 M TRIS HCl pH 8.5, 0.05 M Mg Chloride
A3 15% MPD, 0.1 M Na Acetate pH 4.6, 0.02 M Ca Chloride
A4 15% MPD, 5% PEG 4000, 0.1 M Imidazole HCl pH 8.0
A5 15% MPD, 0.1 M Na Citrate pH 5.6, 0.2 M Ammonium Acetate
A6 15% MPD, 0.1 M Na MES pH 6.5, 0.2 M Mg Acetate
B1 15% MPD, 0.1 M Na HEPES pH 7.5, 0.2 M Na Citrate
B2 20% MPD, 0.1 M Na HEPES pH 7.5, 0.1 M Na Citrate
B3 20% MPD, 0.1 M Imidazole HCl pH 8.0
B4 20% MPD, 4% Glycerol, 0.2 M Na Chloride
B5 30% MPD, 0.1 M Na Acetate pH 4.6, 0.02 M Ca Chloride
B6 30% MPD, 0.1 M Na Citrate pH 5.6, 0.2 M Ammonium Acetate
C1 30% MPD, 0.1 M Na MES pH 6.5, 0.2 M Mg Acetate
C2 30% MPD, 0.5 M Ammonium Sulfate, 0.1 M Na HEPES pH 7.5
C3 30% MPD, 0.1 M Na HEPES pH 7.5, 0.2 M Na Citrate
C4 30% MPD, 5% PEG 4000, 0.1 M Na HEPES pH 7.5
C5 30% MPD, 10% PEG 4000, 0.1 M Imidazole HCl pH 8.0
C6 30% MPD, 20% Ethanol
D1 35% MPD
D2 35% MPD, 0.1 M Imidazole HCl pH 8.0
D3 40% MPD, 0.1 M TRIS HCl pH 8.5
D4 47% MPD, 0.1 M Na HEPES pH 7.5
D5 47% MPD, 2% tert.-Butanol
D6 50% MPD

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.