Re: [ccp4bb] seek your opion on this weird diffractio pattern
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 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=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=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/
Re: [ccp4bb] seek your opion on this weird diffractio pattern
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 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=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/ > To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB=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/
Re: [ccp4bb] seek your opion on this weird diffractio pattern
Hi Joseph Great diffraction patterns. As Jon has just said, it could be zinc acetate. There are some very strong spots which would be consistent with a single crystal of this. However, something else seems to be present. Could it instead be PEG crystals with some superlattice repeat? For unit cell dimensions of PEG see https://pubs.acs.org/doi/abs/10.1021/ma60035a005 Some circles giving Bragg spacings would help. Also the rotation range. You should at least be able to estimate some of the cell dimensions and see if they are consistent with PEG, zinc acetate or some alternative. I seem to recall the subject of PEG crystals coming up before. Colin -Original Message- From: CCP4 bulletin board On Behalf Of Joseph Ho Sent: 08 December 2020 15:47 To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] seek your opion on this weird diffractio pattern 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=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/ -- This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail. Any opinions expressed within this e-mail are those of the individual and not necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachments are free from viruses and we cannot accept liability for any damage which you may sustain as a result of software viruses which may be transmitted in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB=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/
Re: [ccp4bb] seek your opion on this weird diffractio pattern
Hello, the first of those diffraction patterns is very beautiful. What was the concentration of zinc acetate? Also, did you keep the crystal? It might be worth prodding it with a needle and if holds together well or if you hear a loud crack it's probably salt. The second image shows a salt-like pattern. I think those lunes of spots in the first image are some sort of disorder in the crystal, which I fear is zinc acetate. Best wishes, Jon Cooper. Sent from ProtonMail mobile Original Message On 8 Dec 2020, 15:46, Joseph Ho 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=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/ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB=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/
