JBS True Blue Crystal Dye

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.

Description: 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 [1].

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.

Selected References:
[1] Wilkosz et al. (1995) Preliminary characterization of EcoRI-DNA co-crystals: incomplete factorial design of oligonucleotide sequences. Acta Cryst. D 51:938.