Dear Alex

All operators of the point group, except identity, are to be present in the "FILE_TSR".
In your case, D7, it will be 13 operators.

In molrep.doc after SRF run, there is a list of all symmetry equivalent peaks of the SRF.
It might be easier to pick required 13 peaks from this list, or this table could help to check
your selection.

Alexei

On 15 Sep 2006, at 15:05, [EMAIL PROTECTED] wrote:

Dear alex and claus,
 
incidentally I got a very similar case last weeks (also D7 point group symmetry, but in P21, 7-fold parrallel to Y :-)
what I am wondering now is how to input this correftly in FILE_TSR.
I assume that it should be sufficient to give the 7-fold and a single 2-fold (since the six others are generated through the 7fold axis). Is this correct? Do I have to take symmetry related dyad axes into account somehow?
 
regards alex
 
 

     Dr. Alexander Pautsch
     Protein Crystallography /Structural Research
     Boehringer Ingelheim Pharma GmbH & Co. KG Deutschland
     Birkendorferstrasse 65
     88400 BIBERACH, Germany
     tel. +49 - (0)7351 - 54 4683
     fax. +49 - (0)7351 - 83 4683
     email [EMAIL PROTECTED]


-----Ursprüngliche Nachricht-----
Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Im Auftrag von Alexei Vagin
Gesendet: Freitag, 15. September 2006 14:25
An: Claus Kuhn
Cc: [email protected]
Betreff: Re: [ccp4bb]: molrep NCS options

Dear Claus,

 I want to clarify the usage of lock-RF related and NCS related keywords.


In the first case, we know relative orientations of molecules but know nothing of their relative positions. Thus, the keyword LOCK is relevant only to the RF. It pushes correct orientations toward the top of the list and/or improves their contrast. The impact of LOCK on the TF is only that (and when) the list of orientations is changed. This is your case. See example of using LOCK in the MOLREP tutorial at 

http://www.ysbl.york.ac.uk/~alexei/molrep.html


(To download the tutorial use the link “tutorial MR” in section “INSTALLATION”)


The NCS and relevant keywords assume that the position of the NCS axis is known. This is unlikely your case. These keywords are used in fitting into EM maps because the point group and the position of axis are assumed before the EM maps (so called EM reconstructions) are generated.


(MOLREP documentation and “tutorial EM” at the above location contain more details)

Regards

Alexei


On 7 Sep 2006, at 15:25, Claus Kuhn wrote:

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Dear all,

I am trying to use NCS information that I gained from self-rotation
function analysis for running MOLREP.
My molecule obeys 72 point group symmetry with the 7-fold axis running
along c, and the 2-folds perpendicular to the 7-fold along b, one of
them being the crystallographic 2-fold (unit cell monoclinic C2, beta
97°, 7copies per AU.
After running a self rotation function with MOLREP or any other program
I can detect the 7fold axis (chi 52, 105, 157) and the 7 2-folds.
I can detect the 7 rotations of my model when computing a rotation
function with MOLREP as well.
I am trying to input the self rotation peaks, define the NCS parameters
(keywords NCS_ID, ANGLES, CENTRE) and run a locked cross rotation
function (keywords LOCK, FILE_TSR and NSRF). Additionally I edit the
rotation list to include just 'my 7 rotations' of the model before
running a translation search
What is the best way to use this information in running MOLREP ??
Is much of that redundant and may it be useless to use NCS_ID when not
knowing the exact centre of the point group ?
Thanks for any suggestions,

/Claus

AG Cramer
Gene Center 
University of Munich
Germany




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