[ccp4bb] mtz for zanuda - which symmetry?
Hi - For Zanuda, the mtz input it wants: what spacegroup are the data meant to be merged to? The highest possible, potentially twinned? Or the lowest possible? I've looked reasonably hard (10min on the manuals and The Google), and the answer did not leap out at me at all. Even though it seems a rather crucial question - or is it not, in which case, why not, what am I missing? phx
Re: [ccp4bb] mtz for zanuda - which symmetry?
Hi Frank, I have not worked with Zanuda, but googled for the manual (first hit; 1sec). It seems that there are 2 modes: 1) to restore the true (higher symmetry) space group after a structure had intentionally been solved in a lower symmetry space group e.g. P1. In this case the option to merge to the highest possible symmetry space group is what would come to my mind. 2) to look for pseudosymmetry. Since pseudosymmetry might have been interpreted as crystallographic symmetry during the previous attempts to process the data, here the option to merge to the lowest possible symmetry would seem most adequate. If there would be reasons to suspect that the data might be potentially twinned, there seems to be a third option available. Of course, there might be a combination of twinning and pseudosymmetry, intentionally attempted to be solved at lower symmetry... For hard problems (in my experience usually the case) one has to try everything. Good luck! herman -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Frank von Delft Sent: Friday, April 26, 2013 10:18 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] mtz for zanuda - which symmetry? Hi - For Zanuda, the mtz input it wants: what spacegroup are the data meant to be merged to? The highest possible, potentially twinned? Or the lowest possible? I've looked reasonably hard (10min on the manuals and The Google), and the answer did not leap out at me at all. Even though it seems a rather crucial question - or is it not, in which case, why not, what am I missing? phx
Re: [ccp4bb] mtz for zanuda - which symmetry?
Yes I know all that; but where are the explicit instructions? (I assume they're there, I just couldn't see them.) On 26/04/2013 10:27, herman.schreu...@sanofi.com wrote: Hi Frank, I have not worked with Zanuda, but googled for the manual (first hit; 1sec). It seems that there are 2 modes: 1) to restore the true (higher symmetry) space group after a structure had intentionally been solved in a lower symmetry space group e.g. P1. In this case the option to merge to the highest possible symmetry space group is what would come to my mind. 2) to look for pseudosymmetry. Since pseudosymmetry might have been interpreted as crystallographic symmetry during the previous attempts to process the data, here the option to merge to the lowest possible symmetry would seem most adequate. If there would be reasons to suspect that the data might be potentially twinned, there seems to be a third option available. Of course, there might be a combination of twinning and pseudosymmetry, intentionally attempted to be solved at lower symmetry... For hard problems (in my experience usually the case) one has to try everything. Good luck! herman -Original Message- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Frank von Delft Sent: Friday, April 26, 2013 10:18 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] mtz for zanuda - which symmetry? Hi - For Zanuda, the mtz input it wants: what spacegroup are the data meant to be merged to? The highest possible, potentially twinned? Or the lowest possible? I've looked reasonably hard (10min on the manuals and The Google), and the answer did not leap out at me at all. Even though it seems a rather crucial question - or is it not, in which case, why not, what am I missing? phx
Re: [ccp4bb] mtz for zanuda - which symmetry?
Input pdb and mtz should form a valid input for refmac, hence the same cell and sym and merged mtz. On 26 Apr 2013, at 09:17, Frank von Delft frank.vonde...@sgc.ox.ac.uk wrote: Hi - For Zanuda, the mtz input it wants: what spacegroup are the data meant to be merged to? The highest possible, potentially twinned? Or the lowest possible? I've looked reasonably hard (10min on the manuals and The Google), and the answer did not leap out at me at all. Even though it seems a rather crucial question - or is it not, in which case, why not, what am I missing? phx -- Scanned by iCritical.
