it's always worth trying optimization, you never know. also try to get a room-temperature diffraction image of your crystal, only then will you know if the cryo or freezing didn't damage it. If at RT it diffracts to high resolution, you will then know that you have to work on the cryo-conditions or on different mounting techniques (https://doi.org/10.1107/S0907444911031210 <https://doi.org/10.1107/S0907444911031210>).
RT diffraction can be done traditionally in a glass capillary, using a plastic capillary (like the Mitegen ones: https://www.mitegen.com/product/micrort-room-temperature-starter-kits/ <https://www.mitegen.com/product/micrort-room-temperature-starter-kits/>), or in-plate, like described in this paper for instance: https://doi.org/10.1107/S0907444911023249 <https://doi.org/10.1107/S0907444911023249>. Yet another option might be controlled dehydration: https://pubs.acs.org/doi/10.1021/cg500890r <https://pubs.acs.org/doi/10.1021/cg500890r>. Mark J van Raaij Dpto de Estructura de Macromoleculas Centro Nacional de Biotecnologia - CSIC calle Darwin 3 E-28049 Madrid, Spain tel. (+34) 91 585 4616 http://wwwuser.cnb.csic.es/~mjvanraaij Editor of Acta Crystallographica F, Structural Biology Communications http://journals.iucr.org/f/ > On 3 Mar 2018, at 02:34, Natalia O <natalie.c...@gmail.com> wrote: > > Hello, > > I got crystals of protein-nucleic acid complex, rod-shape, reproducible, > don’t visibly get damaged upon freezing; however they gave diffraction only > to about 12 A. I tried several crystals. My question is whether such crystals > worth optimization. Clearly a 4A diffracting crystal could potentially be > optimized to 3 – 2.5A, but if the diffraction that I am getting now is 12A it > could suggest that the system is so flexible that getting to 3A with this > crystal form is not possible at all. I just wonder if there is any statistics > or a rule of thumb about what initial diffraction worth optimization? > > Thank you! > -Natalia >
