Dye-ligand chromatography is not really affinity chromatography because they are not natural ligands for the proteins to which they bind. However dye columns bind proteins very well and can lead to satisfactory purification of proteins. In fact, sometimes this binding is even tighter than normal ligands. Dye ligand columns are usually inexpensive and stable and have a high protein binding capacity. That is why dye-ligated base analysis can be one of the valuable steps in protein purification. Source: Handbook of Protein Technology
Operation method
dyestuff mating method
Principle
The selection of suitable dyes for purification of specific proteins is generally determined by repeated experimental comparisons.Cibacron Blue F3GA, a pioneering dye in this field, closely resembles nicotinamide adenine dinucleotide and has been used for purification of kinases, hydrolases, polymerases and other nucleotide-dependent proteins. This binding specificity is not absolute, however, and Cibacron Blue has also been used in the purification of a variety of proteins that do not have nucleotide-binding capabilities. Binding of proteins to dyes may involve hydrophobic, electrostatic, or hydrogen bonding binding forces, among others. Therefore, despite the availability of commercially available kits for screening various dyes, there is no readily available method for selecting the optimal dye for purification of a given protein.Scopes categorizes dyes according to their ability to bind to proteins and recommends a system for selecting the most effective dyes. Dye-matched base chromatography is relatively simple to perform. Dye chromatography column packings based on a number of support media are commercially available, and these recommended commodities are well reproducible. In selecting a suitable dye-ligand, it is very practical to perform several dye-ligand chromatography trials in succession; if the first one does not bind the target protein, perhaps the second one will. When eluting, the vast majority of proteins are eluted by high salt, although other methods are mentioned later. Dye-matched base columns that have a very limited ability to bind the target protein can be improved by lowering the pH of the solution or by applying divalent or trivalent cations. In conclusion, by following such approaches as those mentioned above, dye-matched base analysis will play an important role in protein purification.
Materials and Instruments
Protein Sample Solution Move Before starting the chromatographic purification of a protein by dye preparation, the dye to be used must be determined. As mentioned earlier, a small-scale (1 ml column) screening with different dye columns is required, and the strategy recommended by Scopes can be used as a reference. In addition, further small-scale experiments can be used to optimize the elution parameters. It is important to note that a dye ligand column that binds to many proteins but not to the target protein is very useful. It can be an excellent step for removing heterogeneous proteins before final purification. The following describes a protocol for washing a Cibacron Blue F3GA column with a high salt solution. 1. Load a column with 5 ml of Cibacron Blue F3GA-agarose. For most practical applications, a short, thick column should give satisfactory results. Longer, thinner columns are more often used for purification of weakly bound proteins, although the flow rate will be reduced; 2. equilibrate the packed column with 10 times the bed volume of chromatography buffer (e.g., 20 mmol/L, pH 8.0 Tris-HCl, 0.1 mol/L NaCl); 3. In order to meet the sample uptake requirements, the protein sample solution needs to be converted to conditions approximating those of the chromatography buffer, i.e., by dialysis with the chromatography buffer or by 1:1 dilution. The sample solution should be clarified by centrifugation or filtration prior to sampling. 5 ml columns are capable of sampling 50 to 200 mg of protein. Unless the protein binding capacity is very high, protein concentrations should normally be in the range of 10 to 20 mg/ml. 4; 4. Sample onto a chromatography column. 5; 5. Wash the column with 5 times the bed volume of Chromatography Buffer or until the A280 value returns to baseline. 6; 6. elute the target protein with 5 times the column bed volume of elution buffer (e.g., 20 mmol/L, pH 8.0 Tris-HCl, 0.1 mol/L NaCl); 7. detection of target proteins in eluted fractions and pooling of fractions containing active target proteins; 8. Regeneration chromatography column. Wash the column with 3 times the bed volume of 1 mmol/L NaOH, and then wash the column with 10 times the volume of chromatographic buffer containing 0.02% NaN3. For more product details, please visit Aladdin Scientific website.
Tris-HCl NaCl NaOH NaN3
Chromatography column