Methylene Blue hydrated
For in vitro use only!
Shipping: shipped at ambient temperature
Storage Conditions: store at ambient temperature
Shelf Life: 12 months
Molecular Formula: C16H18ClN3S * H2O
Molecular Weight: 319.85 g/mol (anhydrous)
EC number: 200-515-2
JBS True Blue is a crystal dye used to stain macromolecular crystals, i.e. protein, peptide and nucleic acid crystals in order to differentiate them from small molecules and salt crystals.
Crystallization screening with high concentrations of precipitant and salt may lead to the formation of salt crystals. It is quite difficult to make a distinction between these false positives and true protein crystals.
Staining of crystals with appropriate dyes is a very straightforward method to differentiate between macromolecular crystals and salt crystals .
Protein and salt crystals differ substantially in their solvent content. Small crystal dyes, like JBS True Blue, are able to permeate the solvent channels of a protein, thus coloring the protein blue. In contrast, salt crystals are tightly packed and do not possess large solvent channels. They will therefore remain colourless.
Simply add 0.5 μl of JBS True Blue to the crystallization drop containing the crystals of interest.
JBS True Blue colors protein crystals after a few minutes. Even if the color of the solution is only faintly blue under the microscope, proteins will be stained within 5-15 min.
Very occasionally, it has been reported that protein crystals did not absorb crystal dyes .
Methylene Blue is a harmful substance if swallowed. Work carefully and wear gloves when handling the dye. Under fire conditions it emits toxic fumes.
 Wilkosz et al. (1995) Preliminary characterization of EcoRI-DNA co-crystals: incomplete factorial design of oligonucleotide sequences. Acta Cryst. D 51:938.
 Eckert et al. (2003) Crystallization and preliminary X-ray analysis of Alicyclobacillus acidocaldarius endoglucanase CelA. Acta Cryst. D 59:139.