Dear Xiao and Hans:
Thanks for your reply. We tried to index it but failed.
On Mon, Mar 12, 2018 at 11:15 PM, Xiao Lei <xiaolei...@gmail.com> wrote:
> did you try to index it? the cell dimensions may give you hint.
> On Mon, Mar 12, 2018 at 4:40 AM, Joseph Ho <sbddintai...@gmail.com> wrote:
>> Dear all:
>> I would like to seek your wisdom on our latest diffraction pattern. We
>> have been working on protein/DNA complex. The protein and DNA have
>> similar MW. By binding assay, we know the minimal length of DNA. (The
>> Kd is 0.1-1 microMolar and we can see the complex formation in size
>> exclusion chromatography up to 200mM NaCl but also some unbound form)
>> After trying different length of DNA, we recently obtained many
>> crystal hits (the percipient is either PEG400 or MPD). The final ratio
>> (prior to protein crystallization) between protein and DNA is 1:1.6
>> considering some loss of protein during concentration. The crystal is
>> birefringent. Since high conc. of PEG400 (MPD), the crystals were
>> directly frozen in liquid N2. However, crystals only diffract to 8-10
>> angstrom (anisotropic) and also weird striking line are present
>> (please see attachment). Do you think if it is DNA alone crystal or
>> protein/DNA complex crystal?
>> How should I improve the diffraction quality?
>> PS. We have done some tests. For example, set up the same conditions
>> with DNA alone. I also tried to dissolve crystals in Bradford assay
>> solution and I believe I saw some blueish color. But none of these
>> tests are conclusive.
>> Thanks for your suggestion.