Dear Brett, We have seen this behaviour several times for different adenovirus fibre head proteins and don't really have an explanation for it. We have always set the peaks up separately when we had enough protein. For this purification, as you don't have enough protein to pool them separately, I would pool them together and do a first crystallisation screen. But I would also immediately start a larger scale purification so you in the next crystallisation trial you can set the peaks up separately. If you are lucky, by the time you have done the second prep, from the first screen you may have some conditions to optimise. If not, the first screen should at least give some ideas about which precipitants, pHs and perhaps additives are most suitable. Mark
On 14 Dec 2013, at 13:16, Acoot Brett wrote: > Dear All, > > When I purified my protein by ion exchange chromatography for > crystallization, there were several peaks containing the target protein as > analyzed by SDS-PAGE. All these peaks have the same MW as determined by gel > filtration coupled MALLS. > > For crystallization purpose, can I merge the corresponding ion exchange > chromatography peaks together? Otherwise the protein yield will be too low. > And how to explain the heterogeneity by ion exchange chromatography in this > situation? > > I am looking forward to getting a reply from you. > > Acoot
