Dear Maria - Lipid diffraction resembles powder diffraction rather than discrete spots - you can see examples in Cherezov's 2002 Biophys J article, for example - so you wouldn't mistake them for protein diffraction. If not a case of overlooked predictions as Kay suggests, you have probably crystallized either a small molecule, a protein contaminant, or a proteolytic fragment of your protein. I have accidentally crystallized a contaminating enzyme at low enough concentration that it wasn't visible on SDS PAGE; I could only track it by activity. If Contaminer doesn't reveal anything and you don't believe you have salt crystals, you probably need to do some mass spec to figure out what species in your drop.
Best of luck Kevin -- Kevin Jude, PhD Structural Biology Research Specialist, Garcia Lab Howard Hughes Medical Institute Stanford University School of Medicine Beckman B177, 279 Campus Drive, Stanford CA 94305 Phone: (650) 723-6431 On Fri, May 22, 2020 at 3:10 AM Demou, Maria <maria.demou...@ucl.ac.uk> wrote: > Dear all, > I have a question that may have a straight forward answer, and was > wondering if this is a common issue. We have a protein crystallised in I222 > space group. This is CRP, but the monomer/pentamer is not predicted to fit > in this space group. Is there a possibility of the lipid cubic phase being > crystallised on it's own, or is there any other obvious reason? > > Thank you, > Maria > > > ------------------------------ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?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/
