There are multiple avenues you could explore. If you think handling is an issue, you could look into growing and collecting with "in situ" plates.
You could test for diffraction at room temp, or even get a full data set at room temp by combining data from multiple crystals. If diffraction is not good at room temp, it is probably not going to be better under cryo conditions. As for cryo, instead of trying cryoprotectant A or cryoprotectant B, you could try a mixture of multiple cryoprotectants: https://pubs.acs.org/doi/abs/10.1021/acs.cgd.5b01692 Use of Multiple Cryoprotectants to Improve Diffraction Quality from Protein Crystals Senda, et al. https://doi.org/10.1021/acs.cgd.5b01692 Evidence of Kinetic Cooperativity in Dimeric Ketopantoate Reductase from Staphylococcus aureus JE Sanchez, PG Gross, RW Goetze, RM Walsh Jr, WB Peeples, ZA Wood Biochemistry 54 (21), 3360-3369 ======================================================================= All Things Serve the Beam ======================================================================= David J. Schuller modern man in a post-modern world MacCHESS, Cornell University [email protected] ________________________________ From: CCP4 bulletin board <[email protected]> on behalf of Blake, Morgan Elizabeth <[email protected]> Sent: Wednesday, November 22, 2023 11:44 AM To: [email protected] <[email protected]> Subject: [ccp4bb] Fragile Crystals Hello! I am a PhD student working on a crystallography project to wrap up my dissertation research. I have purified a complex of two proteins, and I can consistently grow crystals in 10% PEG3350, 0.2M KSCN, 0.1M BIS-TRIS propane pH 7.5. These crystals have sharp edges and can grow to a large size (greater than 0.5 mm), but the crystals seem to be very fragile. When we open the drops to harvest the crystals, we have little time to harvest the crystals before they crack. When we move the crystals to a cryoprotectant, over time they start fracturing. We've tried using different percentages of glycerol, ethylene glycol, PEG400, and oil for cryoprotectants with no success. Needless to say, the crystals do not diffract well, with spot patterns that look very streaky/mosaic, which I presume is due to the defects that we see in harvesting/handling. We have screened for alternate crystallization conditions, but we seem to get the same morphology in other conditions. Does anyone have suggestions for additives we could use post-crystallization to help stabilize our crystals? Thanks for your advice! ________________________________ To unsubscribe from the CCP4BB list, click the following link: 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/
