If Paratone oil is too viscous, I recommend perfluoropolyether (PFPE). A lot of small molecule groups use this because it reduces damage to the crystals.
Kris F. Tesh, Ph. D. Department of Biology and Biochemistry University of Houston ________________________________ From: Kelly Daughtry <[email protected]> To: [email protected] Sent: Wednesday, January 22, 2014 9:47 AM Subject: Re: [ccp4bb] Intergrown crystals 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 <[email protected]> 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: [email protected] > >Birmingham, B15 2TT, UK W: http://tinyurl.com/futterer-lab >======================================================================= > > > > > >
