Usually the skin is precipitated protein when it comes into contact with air. In this case, avoiding contact with air may be the only way to avoid the skin, i.e. crystallise using a technique that is not vapour diffusion, but for instance microbatch, microdialysis or free interface diffusion.
On 13 Jan 2014, at 21:02, Debasish Chattopadhyay wrote: > We crystallized a protein at 4 and 22 deg C in different conditions: > > from ammonium sulfate in acetate buffer pH 5 > and > PEG4000 in Hepes buffer at pH 7.5 > > In both cases the drops have a slimy skin (almost feels like DNA). We > therefore think that the skin is generated from the protein. > > I am sure some of you have had similar experiences. I would like your > suggestions about how to avoid the skin. Please note that we are not asking > for suggestions on how to handle the skin (such as using various tools) we > are only interested in knowing if there is a way to prevent the formation of > the skin. > > Thank you so much > > Debasish > > Ph: (205)934-0124; Fax: (205)934-0480 >
