Macromolecular X-Ray Crystallography Core Services


Researchers are responsible for making their own macromolecules in milligram quantities and in highly purified form. The core staff will assist with handling of macromolecules for structure analysis.

Consultation: Advising investigators how to take advantage of this technology and pursue high-resolution structural studies of their macromolecule of interest. Services covered include developing custom strategies for finding structure solutions, providing answers to protein expression, purification, and crystallization needs, and addressing data collection requirements. Assistance with grant writing and manuscript preparation is also offered.

Training: Training is available for unassisted use of the crystallization robot, imager and X-ray machine.

Crystallization setup: Both assisted and unassisted services. Robotic crystal growth screening in 96-well plates using the hanging- or sitting-drop vapor diffusion technique.

Imaging crystallization plates: Both assisted and unassisted services. The Formulatrix Rock Imager 2 can image and record different crystallization plate formats. Introducing a new core service: UV fluorescence imaging detects the fluorescence signal from tryptophan and can be used to differentiate protein crystals from salt. For macromolecules with low tryptophan content, we can label the macromolecule with a fluorescent dye and use fluorescence imaging to detect protein crystals. The multi-fluorescence imaging option enables detection of macromolecular complexes by labeling one or more components with a different fluorophore. Imaging using the suitable fluorescent channel enables analysis of the crystal content prior to performing an actual diffraction experiment. 

Crystal optimization: The core staff offers service to further optimize crystal growth.

Cryo optimization: The core staff offers service to identify cryo-protectants.

X-ray data collection: Both assisted and unassisted services. For assisted service, core staff will collect data using the in-house X-ray source. Custom data collection by experienced core staff and convenience (e.g. no travel or shipping of crystals) are some of the advantages of utilizing the core over national facilities. The project stays under control of the researcher. The core staff personnel can provide immediate feed-back allowing for optimization of the diffraction experiment or as requested by the investigator.

Access to National Synchrotron facilities: Assisted data collection at the Advance Photon Source at Argonne National Laboratory is available. This service is through the Core for Biomolecular Structure and Function (CBSF) at the Univ. of Texas MDACC. Synchrotron preparation is assisted by BCM X-ray core staff.

Data processing: The core staff will process X-ray diffraction data on behalf of the investigator to identify the crystal space group, unit cell parameters, and crystal diffraction limit. Obtaining those preliminary data is crucial to secure NIH funding by demonstrating feasibility of the proposed research.

Structure Determination: Custom service to determine the crystal structure of a macromolecule of interest. The cost for this service will depend on the difficulty and scope of the project.