Our xTractor Buffer gently but efficiently disrupts bacterial cells for protein purification. The extraction method is simple. Just resuspend the cell pellet in the buffer (1:20 w/v) and mix gently for 10 minutes.
The short incubation period is an advantage when proteins are susceptible to proteases. In addition, this method of membrane disruption is highly efficient, producing a higher protein purity and yield. After extraction, simply centrifuge or filter the lysate and load it onto your favorite purification column. In this case, a TALON Metal Affinity Resin was used for his-tagged proteins.
Sonication
Thanks to its mild, nondenaturing formulation, xTractor Buffer outperformed sonication methods by allowing greater retention of biological activity as well as higher protein yield.
For each condition shown below, protein was isolated from a 1.7-g pellet of E. coli cells expressing his-tagged β-galactosidase (left gel) or his-tagged GFPuv protein (right gel). Lanes 1 and 3 show total lysate, while Lanes 2 and 4 show target protein after column purification. Note the excellent recovery of the higher molecular weight protein, β-galactosidase, in particular.
Improved recovery of β-gal and GFPuv: xTractor Buffer vs. sonication.
The xTractor method doesn’t denature or shear the proteins, so the odds of preserving valuable biological activity are improved. The table below shows xTractor Buffer’s superior yield and retention of activity. Protein activity is expressed in either relative luminescence units (β-Gal) or relative fluorescence units (GFPuv).
Comparison of xTractor Buffer to sonication-based methods
Protein
Extraction method
Fraction
Protein (mg)
Activity
β-Gal
Sonication
Total lysate
28.6
872
Purified protein
0.6
2,115
xTractor Buffer Kit (with lysozyme and DNase I)
Total lysate
122.1
2,277
Purified protein
0.9
3,054
GFPuv
Sonication
Total lysate
40.7
2,247
Purified protein
1.5
3,426
xTractor Buffer
Total lysate
87.0
2,142
Purified protein
1.8
3,514
High MW
Lysozyme and DNase I (supplied as part of the xTractor Buffer Kit) can be added to help isolate high molecular weight proteins, which cannot be extracted unless the membranes are completely disrupted. The addition of lysozyme to these extractions of equally sized E. coli pellets provides a greater representation of high molecular weight proteins in the crude lysates.
Improved recovery of high MW proteins: xTractor Buffer alone vs. xTractor Buffer kit
Conclusion
Our xTractor Buffer allows for rapid, easy, and high-yield protein extraction from samples at any scale, with a mild formulation that allows better retention of biological activity. While conventional methods require formulation of extraction buffers or risk sample loss (e.g., foaming from sonication), our xTractor Buffer provides superior performance in a convenient, ready-to-use format to accelerate your research.
Related Products
xTractor Buffer—reagent for protein extraction
This cell lysis method is simple, efficient, and suitable for protein extraction from bacterial, yeast, mammalian, and baculovirus-infected cells. Its mild, non-denaturing extraction helps preserve biological activity. xTractor Buffer is available alone or as part of a kit with components for optimal yield of high molecular weight proteins.
There is a constant need for faster, more efficient antibody and protein purification processes at any scale. Capturem membrane technology allows for purification directly from complex matrices, such as cell supernatants, in minutes. This technology also provides highly purified and concentrated antibodies and his-tagged proteins, even from samples containing additives not compatible with other purification technologies.
