Dear all,

          We work with lipid droplet binding proteins in our group. These proteins behave more like membrane associated proteins, have a very hydrophobic surface and require detergents right from solubilization to crytallization.

          We use 1% DDM for solubilization, 0.03% DDM throughout affinity chromatography and exchange 3X CMC of OG and LDAO in gel-filtration column for crystallization. Previously, we used to use concentrators with 30kda cut off but recently got suggestions to use higher cut off concentrators. Our proteins arent generally big and are less than 100kda.

          Now my question is that, we havent really got any crystals over a one year period and is it that the 3X CMC of detergents is too much for these globular proteins in the sense it is engulfing the protein on a whole and blocking crystal contacts? Is there a way i could play around with detergents getting closer towards crystals?

          Looking forward to valuable suggestions and thanks very much in anticipation.

Sincerely,
Vasan