Protein crystallographic data acquisition and preliminary analysis using kodak storage phosphor plates

Abstract

X-ray diffraction data from single crystals of typical proteins are very weak, numerous, and subject to systematic errors arising from radiation damage at long exposure times. Compared with films, the Kodak storage phosphor technology described in the accompanying paper [1] offers the prospect of greatly improved signal-to-noise, increased sensitivity particularly at shorter wavelengths, and wide dynamic range, though with more modest spatial resolution. To assess the suitability of this technology for protein crystallographic data collection, we have collected both monochromatic oscillation and wide bandpass Laue data at CHESS on crystals ranging in unit cell size from ∼ 50 Å (lysozyme) to ∼ 300 Å (viruses). A direct comparison of the Kodak storage phosphor with conventional Kodak Direct Exposure Film (DEF-5) was obtained by making immediately sequential exposures on the same crystal with the two detector systems. Even with an exposure time one order of magnitude less than with the corresponding film, the storage phosphor yielded data with improved signal-to-noise. Thus, storage phosphors enable more data to be acquired per crystal, with less radiation damage, and with better precision. Such detectors appear extremely well suited to protein crystallographic applications, both static and time-resolved, with both monochromatic and polychromatic X-ray sources.