*** For details on how to be removed from this list visit the *** *** CCP4 home page http://www.ccp4.ac.uk ***
We are pleased to announce the availability of the XREC software suite for automated crystal centring. XREC processes a series of images, which display different orientations of a crystal flash-cooled in a cryo-loop, determines the crystal centre and provides an estimate of the accuracy (reliability) of the results. The input images can be in grey-scaled PGM, coloured PPM, uncompressed TIFF, PNG or JPEG formats. The beamline operator may write his/her own wrapper to call XREC and, according to its output, to apply corresponding movement of the beamline motors that control the position of the crystalline sample.
The XREC package is freely available to academic users provided that they agree to the XREC academic license conditions and the use of XREC is properly cited. Industrial groups are requested to obtain a commercial license.
As of July 2006 XREC was tested on 227 sets, mostly containing 8 or 9 images with 40 degrees increment. These images were compiled from different beamlines worldwide (EMBL Hamburg, SRS Daresbury, ESRF Grenoble, SSRL Stanford, ALS Berkeley and APS Argonne). In most of the cases XREC appropriately indicated the success or failure of centring by the value of reliability. For details and download please visit www.embl-hamburg.de/XREC.
Babu Pothineni, Tilo Strutz and Victor S. Lamzin
