Some comments on Hampton additive screen for CCP4 BB: We use the Hampton 96-condition additive screen routinely with our nanolitre dispensing robots (Cartesian 8-channel microsys) and often find it gives an improvement in crystal quality. We get it as the individual tubes because to make best use of it we have to reformat it. Annoyingly the volatile additives are in the bottom 1 1/2 rows of the plate so the screen is rearranged to have the non-volatiles in the first 10 columns of a plate and the volatiles in columns 11 and 12. This means that the different types can be handled by our dispenser in different ways. The non-volatiles are diluted with water 1 in 5 in the source plate and then dispensed as equal volume drops with the protein and reservoir (100nl + 100nl +100nl): the excess water will equilibrate away very rapidly in small volume drops. This dilution also makes the solutions easier to handle as the viscosity, solubility and surface tension issues are reduced. The volatile additives are dispensed undiluted as 20ul into the reservoirs only: they should also diffuse into the drops quickly. This means we can get 100s of additive screens out of a single kit in terms of the non-volatiles; the volatiles can be supplemented with larger amounts. We use V-well microtitre plates to store aliquots (5 crystallization plates-worth per plate) of the additive screens frozen to reduce freeze-thaw cycles, and allow them to be used directly on the nanolitre dispenser. Hope this is useful. Tom
** Tom Walter B.Sc. M.Res. ** ** Oxford Protein Production Facility Tel: +44 (0)1865 287747 ** ** Wellcome Trust Centre for Human Genetics Fax: +44 (0)1865 287547 ** ** Roosevelt Drive [EMAIL PROTECTED] ** ** Headington, Oxford OX3 7BN http://www.oppf.ox.ac.uk **
