Generally speaking it is quite hard to crystallize DDM since it is so soluble (>20% in water). You most likely have protein crystals (of course containing a lot of detergent as well) that are just not ordered, presumably because most or all of the lattice contacts are mediated by detergent and not by protein. Unfortunately this is the norm for membrane protein crystallization.
Good luck, Bert ________________________________ From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] on behalf of 于洪军 [hongju...@moon.ibp.ac.cn] Sent: Friday, April 27, 2012 6:07 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] detergent crystal? Hi, I am trying to screen crystals of membrane protein in DDM solutions. I got crystals and its diffraction pattern as I enclosed. Membrane protein crystallization seems quite different from soluble protein. The condition contains PEG400. I learn from other topic here that PEG400 can easily produce DDM detergent crystals. Is it detergent crystal ? Can I tell this from the diffraction pattern? Advices would be greatly appreciated. Thank you. Hongjun
