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

摘要

Abstract: Time-resolved macromolecular x-ray crystallography is anew capability for structural analysis driven bycontinuing improvements in synchrotron x-ray sources,optics, and detectors (image plates and CCDs). Proteincrystal Laue data (stationary crystal and polychromaticx-rays) were recorded at SRS Daresbury station 9.5 andESRF Grenoble beamline 3, and processed with theDaresbury Laue software package. The Laue method allowsexposure times set by the synchrotron electron bunchwidth, e.g. 50 picoseconds. The instruments and methodsdevelopments widen opportunities for perturbationchemical crystallography studies too. A temperaturedependent phase transition of a liquid crystalnickel-octahexylphthalocyanine is studied with a rapidreadout CCD detector. Structure solution by molecularreplacement methods with Laue data is reported fororthorhombic lysozyme. By use of tetragonal lysozyme asa test case it is shown that with fine angularintervals, wide total angular coverage of Laueexposures and the deconvolution of multiples, goodconnectivity of electron density maps can be realized.The monochromatic rotating crystal method offerspossibilites of extremely fast rotations which allow acomplete data set to be recorded onto a single image -large-angle oscillation technique (LOT). the processedLOT data looks promising. LOT electron density maps arepresented. !60