Creative Biostructure offers high-throughput UniCrys™ X-ray crystallography services by using state-of-the-art facilities, and has developed a crystallography pipeline that includes all the stages from protein expression to structure determination. Our experienced scientists can teamwork with customers and accelerate the research progress.
Figure 1. Phase determination from diffraction data
After successful crystallization and the diffraction pattern is obtained with our protein crystallization services, the next challenge is to get an electron density map from which detailed information about the structure can be deduced. This is only possible if the ‘phase problem’ can be solved. Each reflection on the diffraction pattern corresponds to a wave consisting of an amplitude and a phase. The amplitude of diffraction spots can be simply measured by taking the square root of the intensity that X-ray detector records. However, the information on the phases, which contain critical information for determining the electron density distribution in the unit cell, is lost during data collection. The structure of small molecules may be solved in the absence of phase information, but this is not true for macromolecules such as proteins.
Our scientists at Creative Biostructure are highly experienced with phase determination. We use a variety of methods to find initial phases that can subsequently be refined (see Table 1).
Table 1. Protein crystallization services at Creative Biostructure
Molecular Replacement (MR)
Multiple Isomorphous Replacement (MIR)
Single- or Multi-wavelength Anomalous Dispersion (SAD or MAD)
Depending on the quality of the phasing experiment, there can be rather large errors in the phases and thus in the electron density maps. Our scientists will apply their knowledge and expertise, and use a variety of techniques to refine the phases in an iterative manner.
The structural biology team at Creative Biostructure carries out high-resolution structure determination by using both in-house X-ray facility (for trial and optimization) and synchrotron light source (for data collection). High-resolution X-ray data, high-quality density maps, protein structures and statistics will also be made available for the purpose of publication and subsequent studies.
Please feel free to contact us for a detailed quote.