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Hi Daniel, Many thanks – very interesting paper indeed! Noam [en11] From: Bonsor, Daniel [mailto:[log in to unmask]] Sent: Thursday, September 22, 2016 3:44 PM To: אדיר נעם <[log in to unmask]> Subject: Re: [ccp4bb] Overlapping isoforms http://journals.iucr.org/m/issues/2016/04/00/jt5013/ This is a crystal of a milk protein that was isolated in vivo. There are isoforms in the structure. You can see the difference at certain positions in the density. Get Outlook for Android<https://aka.ms/ghei36> ________________________________ From: CCP4 bulletin board <[log in to unmask]<mailto:[log in to unmask]>> on behalf of Noam Adir <[log in to unmask]<mailto:[log in to unmask]>> Sent: Thursday, September 22, 2016 6:31:14 AM To: [log in to unmask]<mailto:[log in to unmask]> Subject: [ccp4bb] Overlapping isoforms Dear all, We have recently determined the structure of a cyanobacterial protein to 2.1A where the asymmetric unit contains a heterodimer. Mass spectrometry of both solution and solubilized crystals show that we have a mixture of two isoforms of both subunits – one is only a relatively minor heterogeneity (95% - 5%), but the second is larger, 70% vs. 30%. The sequence homology between these isoforms is 79% (34/162 non-identical residues) so the crystallographic heterogeneity is not insignificant. We have not found a report of such a large degree of AU heterogeneity in the PDB or the literature – does someone know of a similar case? Thanks, Noam [en11]