The patent-pending XtalTool was developed as a platform for protein X-ray crystallography to be used in all steps from crystallization, ligand soaking and data collection without any direct crystal handling. It is specially interesting therefore for fragile crystals, in which any manipulation might disturb crystal packing and impair diffraction quality.
XtalTools replace regular cover slides used in hanging drop 24 well plates without compromising on optical parameters since crystal growth can be monitored using a regular microscope. The design of XtalTool permits accurate addition and removal of ligand, fragment and/or cryoprotectant solutions without disturbance of the crystals. Once crystals are prepared to the individual user's needs, XtalTool can be directly used to collect crystallographic diffraction data at room or cryogenic temperature. Its geometrical design allows high compatibility with most synchrotron and in-house beamlines as it shares the standard 18 mm SPINE length of a regular sample holder. The employed crystal supporting material is X-ray translucent and does not interfere with diffraction data collection.
XtalTool HT is a further development with the same general features as XtalTool, but with a modified geometry of the inner sample holder that can be broken free at predefined breakpoints. The remaining inner sample holder then fits into a SPINE standard magnetic CryoVial and thereby facilitates robot assisted sample mounting. XtalTool HT is available in two sizes (22 and 18 mm diameter) compatible with the two standard 24 well crystallization plate formats. Despite the different outer diameter, the geometry of the inner sample holder is identical.
Feiler et al. (2019) An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering. J. Vis. Exp. 149:e59722.