Protein crystal optimization with detergents
Posted by Peter Nollert on Tue, Feb 23, 2010 @ 07:11 PM
Detergents are an interesting class of molecules, mainly because of their amphipathic, or amphiphilic nature. They like both water & oil and are hence used extensively to keep hydrophobic molecular species dissolved in an aqueous environment. As a result they're used on an industrial scale to clean clothes, but they're also used in protein crystallization. Of course everybody thinks membrane proteins now, but that's not where this blog post is going. Detergents can be used to optimize the crystallization of soluble proteins.
For example, in their 2001 paper Guan et al. describe the optimization of four soluble protein crystallizations with detergents, all resulting in improved crystal quality and crystal growth reproducibility.
The detergents they use are rather diverse: they use Zwittergent, Mega-8, n-Octanoylsucrose, C12E8 and C-HEGA-10. The surprise here is that none of these detergents - with the exception of C12E8 - are routinely used in membrane protein crystallization trials.
Check out their nice images of protein crystals grown with and without detergent additives.
These dirty crystals could use some detergent scrubbing…
Their simple detergent additive protein crystallization trials have provided the following outcomes:
- polycrystalline -> single crystals
- crystal clusters -> single crystals
- poor X-ray diffraction-> 2.5A diffraction
- non-reproducible -> reproducible
Worth a try, I'd say.
Peter
