Watershed – A Humidity Controlled Workstation For Protein Crystallography
Watershed™ is a humidity controlled workstation for protein crystallography. It prevents drop dehydration during crystals harvesting helping you obtain the best possible diffraction.
Watershed™ will also simplify your crystal mounting allowing you to get the best possible diffraction which in turn allows you to optimize your crystal harvesting and post-growth treatment protocols. Additional benefits of using Watershed™ are:
- Increase drop working times and prevent dried out drops
- Reduce protein precipitation and degradation
- Harvest more crystals from each drop
- Reduce crystal non-isomorphism
- Used controlled dehydration to improve diffraction
- Use with cover slips, glass slides, crystallization plates, or your home X-ray source
Watershed is already used at several facilities including:
- UCSF Macromolecular Structure Group
- Diamond Light Source XChem Pipeline
- The CUNY ASRC Macromolecular Crystallization Facility
- Hauptman-Woodward Medical Research Institute – University of Buffalo
- Max Planck Institute for Developmental Biology
- And more!
The Watershed System was developed in collaboration with Prof. Douglas Juers (Whitman College).
Watershed provides a controlled humidity environment for a wide range of common sample preparation tasks, including
- separating crystals from each other, from precipitate, and from protein skins that may form over crystallization drops;
- soaking crystals in solutions containing cryoprotectants, heavy atoms or ligands;
- harvesting crystals from drops onto X-ray sample mounts;
- blotting or wicking away excess liquid from crystals to reduce background X-ray scatter and increase sample cooling rates during plunge cooling;
- placing crystals in MiTeGen’s MicroRT capillaries or glass capillaries for room temperature data collection; and
- adjusting the hydration of crystals to a desired relative humidity, which may be different from their as-grown relative humidity, to modify protein structure or optimize diffraction properties.
Watershed consists of a water tank, a control unit, and two workstations that provide controllable relative humidities between 50% and >90% RH.
The Humidified Chamber Workstation accepts drops on 18 or 22 mm cover slips or on standard microscope slides. Crystals can be harvested and manipulated within the workstation using standard crystal loops, goniometer bases, and magnetic wands, while being observed from above using a long-working distance stereo microscope. Once mounted, the sample can be transferred to a cryovial containing humid air, and the sample + cryovial can then be removed and transported to, e.g., a cryocooling setup.
The Directed Nozzle Workstation can be used with crystals in multiwell crystallization plates to provide a humidified air flow directed at a well being examined. This workstation can also be used with a laboratory X-ray source to controllably vary the hydration of a crystal during diffraction data collection.
Read the MiTeGen Watershed User Manual to learn more