Dear Sebastiaan, we indeed found something very similar with selecase (see http://www.ncbi.nlm.nih.gov/pubmed/25159620). This is a highly specific metallopeptidase, which is also a metamorphic protein that transits between several stable states, among which only the monomer is the active species. We managed to trap 5 different crystal structures (monomers, three distinct dimers and tetramers)...and all this in a small 110-residue protein! I can provide you with a PDF offline if you are interested. Best wishes, Xavier
On Wed, Apr 8, 2015 at 3:32 PM, Sebastiaan Werten < sebastiaan.wer...@uni-greifswald.de> wrote: > Just for clarity: symmetry mates have been taken into account, the dimer > really doesn't show up in those crystals. > > Seb. > > > At Wednesday, 08-04-2015 on 15:16 Marjolein Thunnissen wrote: > > Hi > > I guess you mean that the protein is a monomer in the asymmetric unit. > It is quite common for multimeric proteins to crystallise such that the > full symmetric complex is formed by applying the crystallographic axis > themselves. So you will need to check the crystallographic contacts to see > whether your protein is an example of such a system. You can use the > program PISA to do this: http://www.ebi.ac.uk/pdbe/pisa/ > > best regards > > Marjolein Thunnissen > > > On 08 Apr 2015, at 15:07, Sebastiaan Werten < > sebastiaan.wer...@uni-greifswald.de> wrote: > > Dear all, > > we are currently working on a protein that is known to exist in a > monomer-dimer equilibrium. At the high concentrations used for > crystallisation assays, the dimer is predominant and the monomer > practically undetectable. > > Nevertheless, one of the crystal forms that we have obtained contains the > monomeric species, not the dimer. > > I was wondering if anyone is aware of similar (published) cases, and if > the phenomenon as such has been discussed in detail anywhere? > > I did literature searches but so far couldn't find anything. > > Any pointers would be much appreciated! > > Best wishes, > > Sebastiaan Werten. > > > > > > > *Dr. Marjolein Thunnissen* > Science Coordinator Structural Biology > > MAX IV Laboratory > Lund University > P.O. Box 118, SE-221 00 Lund, Sweden > Visiting address: Ole Römers väg 1, 223 63 Lund > Telephone: +46 766 32 04 17 > www.maxlab.lu.se > > -- F. Xavier Gomis-Rüth *Research Professor CSIC* Proteolysis Lab Department of Structural Biology Molecular Biology Institute of Barcelona, *Vice-Director* Spanish Research Council CSIC Barcelona Science Park, Helix Building c/ Baldiri Reixac,15-21 *08028 Barcelona (Spain*) ------------------------------------------------------------------- Phone:+34-934 020 186. Fax:+34-934 034 979 e-mail: xgr...@ibmb.csic.es Lab-Homepage: www.ibmb.csic.es/home/xgomis
