An instructional video on the application of cryocrystallographic techniques.

Richard L Walter, Matthew C Slaybaugh and Steven E Ealick: The practice of collecting macromolecular diffraction data at liquid nitrogen temperatures has become routine in many laboratories throughout the world. So far, the dissemination of information concerning the techniques involved has been largely through personal visits to laboratories already skilled in cryocrystallographic methods. In order to further facilitate the circulation of this information, an instructional video on cryocrystallography has been produced at Cornell University. Comprehensive reviews of these techniques have recently been made and others are pending [[1]xPractical cryocrystallography. Rodgers, D.W. Methods Enzymol. 1995; : in pressSee all References, [2]xCryocrystallography. Rodgers, D.W. Structure. 1994; 2: 1135–1140Abstract | Full Text | Full Text PDF | PubMed | Scopus (161)See all References], but animated visual images, as provided by video, should prove to be a useful adjunct to the static images provided by journal articles, particularly in conveying details of the technical manipulations needed for this method.The video is entitled ‘Cryocrystallography’ and is approximately 43 minutes in length. It is divided into eight sections which give detailed descriptions of all the techniques and equipment (including ordering information) needed to carry out cryocrystallographic data collection and crystal storage. The video focuses largely on the loop-mounting technique developed by Teng [3xMounting of crystals for macromolecular crystallography in a free-standing thin film. Teng, T.Y. J. Appl. Cryst. 1990; 24: 387–391CrossrefSee all References[3] (Figure 1aFigure 1a), but further refinements, by David Rodgers at Harvard as well as researchers from other laboratories, are apparent throughout the video.View Large Image | View Hi-Res Image | Download PowerPoint SlideView Large Image | View Hi-Res Image | Download PowerPoint SlideFigure 1Scenes from the cryocrystallography video. (a) A frozen, loop-mounted protein crystal illustrating successful application of low-temperature techniques. (b) Live footage is used to illustrate the techniques necessary for the cryocrystallographic methods.The viewer is first introduced to cryocrystallography and its benefits and pitfalls. After this, all sections consist of detailed step-by-step demonstrations of the techniques, using animated schematics and live footage whenever possible (Figure 1bFigure 1b). Techniques are discussed for the production of crystal mounting loops and the modification of standard goniometer heads for low-temperature work. The use of cryostats is described with emphasis on practical suggestions for the operation of the Molecular Structure Corporation device (MSC, The Woodlands, TX), as used at the Cornell High Energy Synchrotron Source (CHESS). In subsequent sections, emphasis is placed upon preparation of crystals for low-temperature work, including selection of cryoprotectants and assessing the effects of cryoprotectants upon crystals. Techniques for loop-mounting crystals and freezing them directly in the coldstream are illustrated, along with criteria for assessing the success of the freeze. In the final technical section, freezing, storage, and transport of crystals in both liquid nitrogen and solid cryogens (such as propane and freons) are discussed. As a conclusion, several structural results using low-temperature techniques are shown. The final segment of the video presents a comprehensive list of literature pertinent to the field.The video will be provided on request, free of charge, simply by providing a mailing address. This can be done by contacting the authors either by electronic mail (see3@cornell.edu) or by conventional mail. In order to keep the cost of production low, the video can only be supplied in standard VHS format. The production of this video was supported by MacCHESS (NIH RR-01646) and the WM Keck Laboratory for Molecular Structure at Cornell.