The first is a very interesting pattern! - It would be good to know more about exactly how the patterns were taken, camera length and dimensions to determine the spacings. - The first patterns look very strongly like Bessel functions of a helical diffraction pattern that is then sampled by a crystal lattice. The helices of your 8kDa protein would have made very well ordered crystals, with the axis of the helices almost parallel to the horizontal (mounting pin) in the 30 deg pattern. It looks as if one of the crystal axes is exactly along the helix axis. The other 180 deg and 90 deg patterns have the axis of the helix of 8kDa subunits inclined at some calculable angle. You should be able to deduce the helical pitch and radius, and the crystal repeats hence the entire packing in the crystal, - and the structure of the 8kDa subunits.
The second patterns look like salt- probably some form hydrated zinc acetate. Cell dimensions should tell you what it is exactly. Many thanks for interesting puzzle. I’d love to see the result! Robert Stroud str...@msg.ucsf.edu 415 987 7535 > On Dec 8, 2020, at 7:46 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/ > <diffract1.PNG><diffract2.PNG> ######################################################################## 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/
