Actually, DDM is the most successfully used detergent for membrane protein crystallization. See Newstead et al, Protein Sci. 17:466. But yes, the rule of thumb is that detergents that form smaller micelles give better diffracting crystals, but are more destabilizing.
Ho Ho Leung Ng University of Hawaii at Manoa Assistant Professor, Department of Chemistry h...@hawaii.edu On Mon, Mar 26, 2012 at 1:06 PM, CCP4BB automatic digest system <lists...@jiscmail.ac.uk> wrote: > Date: Mon, 26 Mar 2012 17:39:57 +0000 > From: Joao Dias <joao.d...@heptares.com> > Subject: Re: DDM > > Kasia, > A lot of people uses DDM to purify membrane proteins, not a lot of people > crystallises them. > If you want to crystallise a protein purified in DDM, then you should use LCP. > If you go for vapour diffusion, you should exchange the DDM for a detergent > with a smaller micelle size otherwise you might get crystals but it is > difficult to get good diffraction. Try mixed micelles for example. > Typically use 0.05% DDM during purification and use 100kDa cut-off membranes > in order to prevent detergent concentration. > For extraction it depends on your protein and expression system but you can > see in the literature values between 0.5-2% being used successfully. > Good luck. > Cheers, > Joao > > Joao Dias, Ph.D. > > Senior Scientist > Heptares Therapeutics Ltd > BioPark, Broadwater Road, > Welwyn Garden City, > Herts, AL7 3AX > UK
