Member since: 2012
Application Area: Proteins crystallization
"To find a suitable concentration for your pure protein to be crystallized will be sometime challenging. To help resolve this problem, Hampton Research has formulated four solutions containing screen called Pre-Crystallization Screen(Test). The suitable protein concentration can be checked by using this screen. The protein is taken to a 10-15 mg/ml and then this test is performed. If the protein gives an amorphous precipitate this is a good concentration. But if the protein gives a heavy precipitate then it should be diluted. If the protein do not give any of the above then it should be concentrated more. The test is usually repeated as many as possible to find a good precipitate. I recommend doing this test before crystallization."
Sample concentration is a significant crystallization variable. Samples too concentrated can result in amorphous precipitate, while samples too dilute can result in clear drops. Precipitate and clear drops are typical crystallization screen results for reagent conditions which do not promote crystallization and are part of every crystallization screen.
However, by optimizing protein concentration for the screen, the number of clear and precipitate results can often be reduced, which in turn results in more efficient sample utilization while at the same time enhancing the chances for crystallization. PCT can minimize or prevent situations where a screen results in an over abundance of precipitate or clear drops.
The PCT kit contains 4 unique, preformulated, sterile filtered reagents used to evaluate protein concentration for crystallization screening. Initially, the sample protein is mixed with two of the reagents to determine if the protein concentration is appropriate for crystallization screening. If the protein is very sensitive to salt and polymer concentration, based on initial PCT results, the protein may be evaluated using a second set of PCT reagents.
PCT results will then provide insight to either the appropriate sample concentration or indicate that other diagnostic testing such as native gel electrophoresis or dynamic light scattering should be performed to demonstrate sample homogeneity appropriate for crystallization.
PCT™ Pre-Crystallization Test Features: