Hi Rakesh, The first question I have is: why do the crystals dissolve after some time? Did you use a ligand for crystallization that might be turned-over by the protein? What I would do first in your case is to try to find a stabilizing buffer. Since you have obtained nice-looking crystals, there is no need any more to stay at the solubility limit of the protein to allow crystal growth and you can move to a region in the phase-diagram where the protein is no longer soluble.
In practice, this would meant that if your crystals grow at say 25% PEG, you transfer them to a buffer with 30% or even 35% PEG. With a significantly higher precipitant concentration, chances are that your crystals will no longer dissolve. Also, the higher PEG or other precipitant concentration may pull some water from your crystals, resulting in a tighter crystal packing, similar to what is done with crystal dehydration devices like the free-mounter. However, it may also be that your crystals are intrinsically disordered, but if you do not try it, you will never know. Best regards, Herman Von: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> Im Auftrag von Rakesh Chatterjee Gesendet: Dienstag, 27. Juli 2021 17:55 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] Problems with crystals diffracting Hi everyone I was working on a protein complex where one protein binds with the other protein majorly based on its surface charge. The protein complex yields nice crystals but does not diffract. Additionally the crystals used to dissolve within the drop when allowed for incubation both at 18 degrees and 4 degrees. Repeated rMMS microseeding, construct variations and changes in purification strategies did not yield any diffractions. Conditions involved for the protein complexes primarily involved PEG with various strengths and pH variations. Looking for your suggestions and valuable ideas Thanks in advance Dr Rakesh Chatterjee Umea University Umea Sweden ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1<https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1> ######################################################################## 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/
