Accelerated Technologies Center for Gene to 3D Structure

We have developed a DETECT-X (Difference Extinction for the Detection of Crystals) microscope system and associated image processing algorithms for improved crystal imaging. The DETECT-X microscope is a fully automated polarization and UV fluorescence microscope for inspecting crystallization trials. Through the analysis of four polarization images (at 0°, 45°, 90°, 135°) the system calculates quantitative values for the transmission, the birefringence, and the extinction angle at each pixel. Each of these values can then be displayed as a false-color image and together these images provide better contrast for identifying crystalline material. In its birefringence microscopy mode the DETECT-X microscope produces quantitative images of crystals depicting the orientation of the slow optical axis of protein crystals and their orientation-independent, quantitative birefringence. Such images allow the detection of crystals that are masked by precipitate. Spherulites and microcrystalline material can be readily distinguished from amorphous precipitate. As a result, there are fewer false negatives and more potential leads are identified for crystal optimization. Twinned crystals can also be readily identified, so that the best crystals for diffraction experiments can be selected. The use of in situ UV fluorescence microscopy also helps to distinguish between salt crystals and protein crystals. It is anticipated that DETECT-X microcopy improved efficiencies in optical screening of protein crystallization trials.

Contact: Peter Nollert, pnollert@emeraldbiosystems.com