Time-resolved biological and perturbation chemical crystallography: Laue and monochromatic developments

Time-resolved macromolecular x-ray crystallography is a new capability for structural analysis driven by continuing improvements in synchrotron x-ray sources, optics, and detectors (image plates and CCDs). Protein crystal Laue data (stationary crystal and polychromatic x-rays) were recorded at SRS Daresbury station 9.5 and ESRF Grenoble beamline 3, and processed with the Daresbury Laue software package. The Laue method allows exposure times set by the synchrotron electron bunch width, e.g. 50 picoseconds. The instruments and methods developments widen opportunities for perturbation chemical crystallography studies too. A temperature dependent phase transition of a liquid crystal nickel-octahexylphthalocyanine is studied with a rapid readout CCD detector. Structure solution by molecular replacement methods with Laue data is reported for orthorhombic lysozyme. By use of tetragonal lysozyme as a test case it is shown that with fine angular intervals, wide total angular coverage of Laue exposures and the deconvolution of multiples, good connectivity of electron density maps can be realized. The monochromatic rotating crystal method offers possibilites of extremely fast rotations which allow a complete data set to be recorded onto a single image - large-angle oscillation technique (LOT). the processed LOT data looks promising. LOT electron density maps are presented.