Re: [ccp4bb] small lines in diffraction patternActa Cryst. (1998). D54, 848-853 [ doi:10.1107/S0907444998001875 ]
A Description of Imperfections in Protein Crystals C. Nave Abstract: An analysis is given of the contribution of various crystal imperfections to the rocking widths of reflections and the divergence of the diffracted beams. The crystal imperfections are the angular spread of the mosaic blocks in the crystal, the size of the mosaic blocks and the variation in cell dimensions between blocks. The analysis has implications for improving crystal perfection, defining data-collection requirements and for data-processing procedures. Measurements on crystals of tetragonal lysozyme at room temperature and 100 K were made in order to illustrate how parameters describing the crystal imperfections can be obtained. At 100 K, the dominant imperfection appeared to be a variation in unit-cell dimensions in the crystal. ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: j-kell...@northwestern.edu ******************************************* ----- Original Message ----- From: Jacob Keller To: CCP4BB@JISCMAIL.AC.UK Sent: Wednesday, January 28, 2009 11:57 AM Subject: Re: [ccp4bb] small lines in diffraction pattern I had thought that in a previous thread, we had all come to a consensus that actually the largest source of what is normally explained as "mosaicity" is really differences in unit cell size, due perhaps to uneven shrinkage in crystals upon freezing or otherwise. I believe that there was actually an acta cryst paper which investigated all of the various ingredients of "mosaicity" which supports this (this is why I said it.) Jacob ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: j-kell...@northwestern.edu *******************************************
