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abstracts
As crystallographers face increasing problems with crystallizing new proteins, in-situ screening in crystallization trays at room temperature is experiencing a renaissance. It saves a lot of time when screening large numbers of crystallization hits and it helps avoid crystal damage caused by human manipulation error (harsh manual handling, bad freezing) or changes in crystal properties (dehydration, wrong cryo-conditions). In certain cases, it is also possible to go beyond screening and collect enough data for structure solution, especially on an X-ray home source where a less intense beam helps minimize the devastations of radiation damage occurring at room temperature. The Rigaku PlateMate has proved itself as an efficient and easy-to-use in-situ screening tool on the field for the past two years. It is as easily mounted on a goniometer as a regular goniometer head and thanks to a plate adapter with SBS footprints, it accommodates most 96-wells plate types, from sitting and hanging drop to LCP plates. In addition, thanks to its narrow dimensions and aided by software to prevent collisions with the detector and the crystal viewing camera, the PlateMate can be used to easily collect data from crystals in situ. In this work, we present structure solution results obtained from data collected with the PlateMate on crystals from various proteins (native crystals or containing gold or iodine) and using one or multiple crystals to make up a complete data set.
abstracts
RigakuIntegrate is a new single crystal integration program designed to increase integration accuracy by optimizing the reflection domain to exclude all but relevant elastic scattering. Instead of integrating over a shoebox domain, RigakuIntegrate sums over a tailored detector region that incorporates the known diffraction physics of each reflection as it passes through the Ewald sphere, combined with the known properties of the area detector. The reciprocal space reflections are modelled by ellipsoids that account for the crystal radius, beam crossfire, mosaicity, and wavelength dispersion. In case of laboratory sources separate ellipsoids are assigned to each of the Kα1 and Kα2 components. The passage of the reflection through the diffraction condition is modeled by the intersection of the ellipsoid(s) with the Ewald sphere, resulting in a set of ellipses. This set of intersection ellipses is then projected onto the detector plane along the scattered ray direction. Interaction with the detector sensor is modeled by appropriate convolution, resulting in reflection-specific integration domains over the surface of the detector. Results from crystals ranging in quality from exquisite (a charge density analysis of oxalic acid at 100K using a RAPID IP detector) to marginal (a highly mosaic and split crystal that refines to R1(all data) = 2.6% using a Pilatus detector) will be presented.
