Hi Joseph, It is a very beautiful crystal with neat diffraction patterns and background, which may suggest a good cryoprotection. Here is my observation from your images.
1. From your image taken at 30 degrees (first page), I believe it is a protein crystal with a larger unit cell length on one dimension, rather than an inorganic crystal. By measuring the distance between two spots in line, you may be able to estimate the length of the unit cell two dimensions. 2. According to the first crystal image, there is a line in the middle of the crystal. If I am correct, it could be that two crystals grew and merged together. I used to have some cases like this. In my case, one half of the crystal showed a hexahedron shape, and another half with a nearly cubic shape. Eventually, the structure was determined in both P3 and P222 with refined conditions, respectively. If this is true in your case, you may have a multi crystal growth. 3. According to the 90 degree angle image on your second page, the diffraction spots at right-bottom corner (4:30 O'Clock), those three spots could be a protein crystal with a shorter length. There could be two possibilities, very anisotropic growth or taking a longer exposures. 4. According to the outlooking of you crystal, it is very possible to carry P3 or P6 symmetry. If this is true, it won't be an inorganic crystal. 5. If you still have crystals from the same drop, you may cut a piece from the right side and take a long shoot. You may have a chance to index it. Best, Kevin On Tue, Dec 8, 2020 at 7:47 AM Joseph Ho <sbddintai...@gmail.com> wrote: > Dear all: > We recently worked on 8kDa protein crystal structure. We obtained > crystals in Zinc acetate and PEG8000 condition. However, we observed > this unusual diffraction patterns. I am wondering if anyone observed > this and know how this can occur. The cryoprotectant is glycerol. > > Thank you for you help > > Joseph > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > > This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a > mailing list hosted by www.jiscmail.ac.uk, terms & conditions are > available at https://www.jiscmail.ac.uk/policyandsecurity/ > -- Kevin Jin Ph.D Sharing knowledge is always joyful......A flash scientist in biology. Website: http://www.jinkai.org/ ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
