Israel, Here is a paper that describes a phenomenon like what you have observed:
Structure. 2003 Feb;11(2):139-45. Dehydration converts DsbG crystal diffraction from low to high resolution. Heras B, Edeling MA, Byriel KA, Jones A, Raina S, Martin JL. And another review that touches briefly on the idea, among other things: Acta Crystallogr D Biol Crystallogr. 2005 Sep;61(Pt 9):1173-80. Epub 2005 Aug 16. Post-crystallization treatments for improving diffraction quality of protein crystals. Heras B, Martin JL. Mike ----- Original Message ----- From: "Israel Sanchez" <israelsan...@gmail.com> To: CCP4BB@JISCMAIL.AC.UK Sent: Sunday, May 1, 2011 10:32:21 AM GMT -08:00 US/Canada Pacific Subject: [ccp4bb] Dehydration treatments Hi folks, I am currently impressed by the efficiency of dehydration treatments over the diffraction capacity of our crystals in one particular condition. Without any treatment the crystals seldom diffract to 20-30A but in our last synchrotron trip the very same crystals, after been incubated with increasing concentration of low molecular weight PEGs diffracted to 6A. I was wondering if anyone has studied these effects in a systematic way. Does anyone on the ccp4bb knows references or has any experience/pseudo-religious believes that do not care to share with the community about this particular topic? Thank you very much in advance!!!! -- Israel Sanchez Fernandez PhD Ramakrishnan-lab MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB2 0QH, UK -- Michael C. Thompson Graduate Student Biochemistry & Molecular Biology Division Department of Chemistry & Biochemistry University of California, Los Angeles mi...@chem.ucla.edu