University of Heidelberg
CellNetworks > CoreFacilities > Protein Crystallization Platform

Protein Crystallization Platform

Crystallization Service

At the beginning of a cystallization project, we discuss with our users the various aspects of such a project, e.g. expression construct design (min/max approach), fusion constructs, optimized protein preparation, complex formation and co-crystallization strategies, use of co-factors and inhibitors. In order to obtain well-diffracting protein or RNA crystals, it is often necessary to revisit and modify these parameters in the course of the project.

Initial Screening

Identifying one or more initial crystallization conditions is the first step on the way to high-quality protein crystals. For this purpose the platform offers 20 "crystallization screens", i.e. compilations of 96 mixtures of various reagents like salts, polymers, and buffers.

Optimization

In order to obtain well diffracting high-quality crystals, it is often necessary to refine the initial crystallization conditions by adding additional chemicals to the inital mixture or by modification of the mixture recipe. The crystallization platform designs and creates fine screens with the in-house stock solutions for refinement of initial crystallization hits.

Monitoring

Crystallization plates are stored at 18°C or 4°C and automatically imaged according to a customisable schedule. The images can be inspected from your own computer via the CrystalTrakWeb interface or at the platform computers. The Formulatrix MUVIS UV microscope allows to distinguish between protein and salt crystals at a very early stage of the project.

Required Sample Volume

The minimal sample volume per crystallization drop is 100 nl, i.e. 10 µl per plate. In order to avoid aspiration of air, we would like to have an additional 5µl of sample.

Sample volume per drop
Sample volume per plate
Total for N plates (μl)
100 nl
10 μl
N x 10 + 5
200 nl
20 μl
N x 20 + 5
500 nl
50 μl
N x 50 + 5

Lipidic Cubic Phase Technique

Crystallization of membrane proteins in lipidic cubic phase (LCP) technique has proven to be highly successful in recent years. The LCP technique allows to keep the membrane protein embedded in a lipidic environment during the crystallization process. The crystallization platform is equipped with an ArtRobbins Gryhon crystallization robot which is especially designed for the LCP technique. Several plate types are in use at the platform (plastic, glass, composite) for initial screening, better crystal harvesting or in-situ crystal characterization.