Hi Tony,

Thanks for your input. However, I am almost towards the end of model building...need to join some loops and so..and that was the R/Rfree...The Scala/Xtriage/Ctruncate output did not show any signs of twining...although in presence of tNCS these tests are all blurred....but even in phaser MR which detected the tNCS vector and corrected it eventually, did not show the presence of twining...I think even without the presence of twining, twin refinement is not a good option to turn on. Please let me know what you think.

Best,
Sudipta.

On Sat, Jul 11, 2015 at 5:39 AM, Antonio Ariza <[log in to unmask]> wrote:

Hi Sudipta,

 

Your R factors don't look horribly high for an initial build and refinement at 3.2A, assuming you still need to substantially improve your structure ... if your structure is basically complete that's obviously a different matter. First of all I would look at your scaling output to check for twinning (aimless and pointless give very good indications) ... or simply re-run your last refmac job with twin refinement "on" and check the log file to see if the programme finds any twinning.

 

Regards,

 

Tony

 

------------------------------------------------------

Dr. Antonio Ariza
University of Oxford
Sir William Dunn School of Pathology
South Parks Road
Oxford
OX1 3RE
From: CCP4 bulletin board [[log in to unmask]] on behalf of Sudipta Bhattacharyya [[log in to unmask]]
Sent: 10 July 2015 19:59
To: [log in to unmask]
Subject: [ccp4bb] refmac5/phenix refinement strategies with 3.2A data with pseudotranslation.

Dear All,

I am  struggling with a 3.2A structure refinement which also suffers from translational NCS issue. Although the maps look very good but R/Rfree is not going down as expected. Could someone please suggest me tricks/tips with Refmac5/Phenix refinement optimization in this regard. The model has 4 molecules/ASU, space group initially appeared P212121 but later was found to be P21212; current R/Rfree is 33/36. Please let me know if you need any further details. Any suggestion/help will be really appreciated.

My best regards,
Sudipta.