Regarding backsoaking [2], This is one of those nice exercises for the reader!
Try raddose calculations with versus without 1 mM heavy-atom compound in the solvent channels. Pete -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Francis E Reyes Sent: Monday, October 04, 2010 9:29 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] Radiation damage with crystals containing metal centers (TaBr people chime in?) Hi all I'm reading a recent review by Elspeth Garman regarding radiation damage (Acta Cryst D) and in this she mentions two ideas regarding metal centers: [1] They (The metal complexes themselves) are quickly reduced [2] Their absorption causes localized heating in the crystal. (This causes the temp to increase above freezing thus allowing OH radicals to diffuse). How is it that people can phase off of TaBr considering [1]? Presumably as TaBr is absorbing x-ray's whatever anomalous signal that was present at the beginning of the collection is either absent/ significantly altered by the time data collection is complete? Regarding [2], is TaBr usually backsoaked (into cryoprotectant not containing TaBr) to reduce it's concentration in the crystal to highly occupied sites? It would seem to me that having a crystal soaked with TaBr would cause more heating than one backsoaked. Thanks F --------------------------------------------- Francis E. Reyes M.Sc. 215 UCB University of Colorado at Boulder gpg --keyserver pgp.mit.edu --recv-keys 67BA8D5D 8AE2 F2F4 90F7 9640 28BC 686F 78FD 6669 67BA 8D5D
