Dear Xiao and Hans: Thanks for your reply. We tried to index it but failed.
Joseph 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. >> >> Joseph > >
