The Zetasizer APS is a robust, simple-to-operate system that uses laser light scattering to determine a number of parameters associated with protein conformation and stability. It integrates a plate sampling system and measurement unit into a single instrument, automating the measurement of samples in industry standard 96- or 384-well plates on as little as 20 μL of recoverable sample.
Dr Maria Håkansson is the MAX-lab crystallization facility manager and senior scientist at SARomics Biostructures. She is one of a number of people within the company to use the Zetasizer APS. “Our primary use of the Zetasizer APS is in screening protein preparations to ensure they are monodisperse and therefore suitable for crystallization,” said Dr Håkansson. “If we find aggregated proteins, then crystallization trials are unlikely to be successful and we know we need to adjust the preparation process. We’ve been running the Zetasizer APS continuously since 2012 and the real beauty is that we simply load the samples in multiwell plates, leave it to run, even overnight, and go back and pick up the results. The system is easy to use, requires little training and, most importantly, the measurements and data are excellent.”
The team at SARomics also uses the Zetasizer APS in other protein screening applications. To screen protein constructs, for example, to check their size and aggregation status, with 20-30 duplicate samples being run routinely. Stability screening of single constructs in a range of buffers is also done to assist with selecting appropriate buffers for crystallization trials. In addition, the Zetasizer APS is used in conjunction with differential scanning fluorimetry to determine protein melting points, the results of which can be correlated with light scattering.
The full automation and low sample requirements of the Zetasizer APS make it ideal for early stage screening. Dual, independent temperature controls for both the plate holder and measurement cell ensure that samples are fully protected throughout the measurement cycle, in order to deliver high accuracy and reproducible results.
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