Klaus, I've had success with using paratone to separate crystal clusters. Paratone is quite viscous, and an excellent cryoprotectant. By dragging your crystal around (gently) through paratone you can sometimes isolate a single crystal. Also, do you have access to a micro-focus beam? You could try centering on different areas of the crystal to identify a singel crystal.
Otherwise, other suggestions of slowing growth rate and micro-seeding should help with your inter-growth problem. Hope this helps, ******************************************************* Kelly Daughtry, Ph.D. IRTA Fellow Mechanisms of Mutation Group Molecular Genetics Laboratory, MD E-301 National Institute of Environmental Health Sciences 111 TW Alexander Drive Research Triangle Park, NC 27709 Tel. (919) 541-3452 ******************************************************* On Wed, Jan 22, 2014 at 10:01 AM, Klaus Fütterer <k.futte...@bham.ac.uk>wrote: > Dear ccp4bb contributors, > > We are dealing with the problem of a protein (~ 50 kDa) that crystallises > readily, but has an annoying habit of forming highly intergrown rods or > needles. > Even when the crystals look optically homogenous under the microcsope, > diffraction is so so (3.5 Å or so on the synchrotron), but patterns reflect > several crystal lattices that the processing software cannot resolve > properly. > > We have tried this: > > - additive screens > - switching the His-tag from N- to C-terminus > - cutting the tag > - thermal stability screens in a variety of buffers > - growth in the presence of potential ligands/substrates > > Any suggestions for tricks that we haven't thought of so far? > > Thank you. > > Klaus > > > ======================================================================= > > Dr. Klaus Fütterer > > School of Biosciences P: +44-(0)-121-414 5895 > University of Birmingham F: +44-(0)-121-414 5925 > Edgbaston E: k.futte...@bham.ac.uk > > Birmingham, B15 2TT, UK W: http://tinyurl.com/futterer-lab > ======================================================================= > > > > > >
