Re: [ccp4bb] Wrong Space Group?

2013-12-14 Thread Kay Diederichs
On Fri, 13 Dec 2013 19:44:44 +, D Bonsor dbon...@ihv.umaryland.edu wrote: Dear D, I agree with Tim and Jürgen that a) the map after Phaser, and before refinement is the most unbiased and should be used for sequence assignment. b) there may be a sequence register shift error that is

[ccp4bb] A question on protein microheterogenity for crystalization

2013-12-14 Thread Acoot Brett
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

Re: [ccp4bb] A question on protein microheterogenity for crystalization

2013-12-14 Thread Bosch, Juergen
Hi Acoot, since they behave differently on IEX, they are different - you would introduce heterogeneity into your crystallization setup, which usually is not a good idea for crystallization in general. Are you using Benzonucleases by any chance in your preparation and if not, that may explain

Re: [ccp4bb] A question on protein microheterogenity for crystalization

2013-12-14 Thread Mark van Raaij
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

Re: [ccp4bb] A question on protein microheterogenity for crystalization

2013-12-14 Thread Xiaodi Yu
Hi Acoot: Can your protein form some kind of dynamic self oligomers? When you test by using the gel-filtration column, if the peak is symmetry? Sometime if the target protein can have week self interaction, you can observe a tailed peak. If the protein can have a strong self interaction, maybe