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webinar_2021-03 [2021/03/12 13:22]
maly screenshot
webinar_2021-03 [2021/03/24 10:09] (current)
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 ====== PAIREF webinar ====== ====== PAIREF webinar ======
  
- 23 Mar 2021, 3pm (CET)+23 Mar 2021, 3pm (CET)
  
-  ​- Introduction to paired refinement. [[Download ​the presentation in PDF]].+=== IMPORTANT: Please install PAIREF and download data before the webinar (instructions below). === 
 + 
 +  ​- Introduction to paired refinement. [[https://​pairef.fjfi.cvut.cz/​docs/​pairef_poli_webinar/​PAIREF_webinar_2021_kolenko.pdf|Download presentation in PDF]].
   - Installation of //PAIREF// for CCP4 and PHENIX users.   - Installation of //PAIREF// for CCP4 and PHENIX users.
   - Short tutorial. [[https://​pairef.fjfi.cvut.cz/​docs/​pairef_poli_webinar/​PAIREF_webinar_poli.zip|Download the archive with the data]].   - Short tutorial. [[https://​pairef.fjfi.cvut.cz/​docs/​pairef_poli_webinar/​PAIREF_webinar_poli.zip|Download the archive with the data]].
   - Discussion.   - Discussion.
 +
 +[[https://​pairef.fjfi.cvut.cz/​docs/​pairef_poli_webinar/​PAIREF_webinar_2021-03.pdf|Download these webinar instructions in PDF]]
 +
 +==== Video recording from the webinar ====
 +
 +[[https://​pairef.fjfi.cvut.cz/​docs/​pairef_poli_webinar/​PAIREF_webinar_23Mar2021_.mp4|{{ ::​pairef_webinar_2021-03_video.gif |}}]]
 +
  
 ===== Tutorial ===== ===== Tutorial =====
 +
 +==== PAIREF installation:​ IMPORTANT: Please install PAIREF before the webinar ====
 +Althought //PAIREF// has been developed to be installed easily, atypical computer setting can cause problems sometimes. Feel free to contact us via email ([[martin.maly@fjfi.cvut.cz]]) and we will help you.
 +
 +//PAIREF// **depends** on the installation of the [[http://​www.ccp4.ac.uk/​|CCP4 Software Suite]] or [[https://​www.phenix-online.org/​|PHENIX]]. In this webinar, we recommend to have the CCP4 Suite installed as we will be focused on that.
 +
 +In GNU/Linux or macOS, just open the terminal. ​
 +
 +In Windows, find the CCP4 console or Phenix Command Prompt in the Start menu and open it (see the screenshots below).
 +
 +{{:​ccp4console.gif?​nolink|}} {{:​phenix_command_prompt.gif?​nolink|}}
 +
 +Now execute the following commands that install PAIREF into CCP4 environment on your computer:
 +<​code>​
 +ccp4-python -m ensurepip --user
 +ccp4-python -m pip install pairef --no-deps --upgrade --user
 +</​code>​
 +
 +If the installation was not successful, please go through the section [[https://​pairef.fjfi.cvut.cz/​docs/​installation.html#​troubleshooting|Installation - Troubleshooting]] in our documentation.
 +
 +**In the end, please check whether the installation was successful: Try to show the help message executing the following command:**
 +
 +<​code>​ccp4-python -m pairef --help</​code>​
 +
 +If the help message appears, the installation seems to be successful. Please download also the data before the webinar - the instruction follows.
  
 ==== Download data ==== ==== Download data ====
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   * Merged diffraction data up to 1.9 Å - //​poli67_1-9A.mtz//​   * Merged diffraction data up to 1.9 Å - //​poli67_1-9A.mtz//​
   * Unmerged diffraction data up to 1.9 Å - //​poli67_XDS_ASCII_1-9A.HKL//​   * Unmerged diffraction data up to 1.9 Å - //​poli67_XDS_ASCII_1-9A.HKL//​
 +
 +**If you have installed //PAIREF// and extract the data, you are ready for the webinar.** :-)
  
 ==== Open console in working directory ==== ==== Open console in working directory ====
 Open terminal (GNU/Linux, macOS) or CCP4 console (Windows) and go to the folder where your structure model and diffraction data are saved. For example, if you saved those three files to folder ''​C:/​Users/​Lab/​PAIREF_tutorial_poli'',​ write ''​cd C:/​Users/​Lab/​PAIREF_tutorial_poli''​ into the console and press ''​Enter''​. Open terminal (GNU/Linux, macOS) or CCP4 console (Windows) and go to the folder where your structure model and diffraction data are saved. For example, if you saved those three files to folder ''​C:/​Users/​Lab/​PAIREF_tutorial_poli'',​ write ''​cd C:/​Users/​Lab/​PAIREF_tutorial_poli''​ into the console and press ''​Enter''​.
- 
-==== Install PAIREF ==== 
-Execute the following command: 
-<​code>​cctbx.python -m pip install pairef --user --no-deps</​code>​ 
  
 ==== Run PAIREF in command line ==== ==== Run PAIREF in command line ====
-We will add three high-resolution shells step by step: 2.3-2.10 Å, 2.1-2.0 Å and 2.0-1.9 Å. Run //PAIREF//: <​code>​cctbx.python -m pairef --XYZIN poli67_webinar_2-3A.pdb --HKLIN poli67_1-9A.mtz -u poli67_XDS_ASCII_1-9A.HKL -r 2.1,2.0,1.9 -w 0.06 -p poli_webinar</​code>​+We will add three high-resolution shells step by step: 2.3-2.10 Å, 2.1-2.0 Å and 2.0-1.9 Å. Run //PAIREF//: <​code>​ccp4-python -m pairef --XYZIN poli67_webinar_2-3A.pdb --HKLIN poli67_1-9A.mtz -u poli67_XDS_ASCII_1-9A.HKL -r 2.1,2.0,1.9 -w 0.06 -p poli_webinar</​code>​
 Note: The structure model was refined using X-ray weight 0.06, we have to keep this setting to gain unbiased results. Note: The structure model was refined using X-ray weight 0.06, we have to keep this setting to gain unbiased results.
  
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 //PAIREF// provides also a [[https://​pairef.fjfi.cvut.cz/​docs/​gui.html|graphical user interface (GUI)]] for intuitive setting of arguments without making up a command. However, it depends on the installation of CCP4 suite. For launching the PAIREF GUI, execute the following command: //PAIREF// provides also a [[https://​pairef.fjfi.cvut.cz/​docs/​gui.html|graphical user interface (GUI)]] for intuitive setting of arguments without making up a command. However, it depends on the installation of CCP4 suite. For launching the PAIREF GUI, execute the following command:
 <​code>​ccp4-python -m pairef --gui</​code>​ <​code>​ccp4-python -m pairef --gui</​code>​
-{{ :pairef_webinar_poli_gui.png?nolink |}}+{{ :pairef_webinal_poli_gui_win.png?nolink |}}
  
  
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 The first thing that should be checked is whether the refinements have converged. Scroll at the very bottom of page, here you can see plots of Rwork and Rfree vs. refinement cycle. We can conclude that all the refinements have converged. The first thing that should be checked is whether the refinements have converged. Scroll at the very bottom of page, here you can see plots of Rwork and Rfree vs. refinement cycle. We can conclude that all the refinements have converged.
  
-Rfree decreased after the addition of shells 2.3-2.10 Å and 2.1-2.0 Å.+Rfree decreased after the addition of shells 2.3-2.10 Å and 2.1-2.0 Å:
  
 {{ :​poli_webinar_r-values.png?​nolink |}} {{ :​poli_webinar_r-values.png?​nolink |}}
  
-Since a perfect model gives an R value of 0.42 against random data (i.e. pure noise) – assuming non-tNCS (translational non-crystallographic symmetry) data from a non-twinned crystal ((Evans, P. R. & Murshudov, G. N. (2013). Acta Cryst. D69, 1204-1214.)) – a higher R value in the (current) high-resolution shell indicates either the involvement of high-resolution data without information content (the data are even worse than noise), or poor quality of the model, or the presence of tNCS. This is indicated for the shell  2.0-1.9 Å.+Since a perfect model gives an R-value of 0.42 against random data (i.e. pure noise) – assuming non-tNCS (translational non-crystallographic symmetry) data from a non-twinned crystal ((Evans, P. R. & Murshudov, G. N. (2013). Acta Cryst. D69, 1204-1214.)) – a higher R-value in the (current) high-resolution shell indicates either the involvement of high-resolution data without information content (the data are even worse than noise), or poor quality of the model, or the presence of tNCS. This is indicated for the shell  2.0-1.9 Å.
 {{ :​poli_webinar_rfree.png?​nolink |}} {{ :​poli_webinar_rfree.png?​nolink |}}
  
-CC* is higher than CCwork in whole resolution range (except the shell 2.0-1.9 Å where CC* is undefined due to negative CC1/​2. ​No overfitting was indicated.+CC* a model-independent measure of noise is in the diffraction data. CC* is higher than CCwork in whole resolution range (except the shell 2.0-1.9 Å where CC* is undefined due to negative CC1/​2. ​Thus, the overfitting was not indicated. To access overfitting,​ it is not needed to test set, so the comparison of CC* with CCwork is much better then with CCfree as CCwork is calculated on more data.
 {{ :​poli_webinar_ccwork.png?​nolink |}} {{ :​poli_webinar_ccwork.png?​nolink |}}
  
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 07      2.10   ​2.00 ​ 49772   ​4021 ​  ​12.38 ​ 98.51       ​0.3 ​    ​0.1 ​  ​16.989 ​  ​17.721 ​   4.963   ​0.027 ​  ​0.008 ​  ​0.2293 07      2.10   ​2.00 ​ 49772   ​4021 ​  ​12.38 ​ 98.51       ​0.3 ​    ​0.1 ​  ​16.989 ​  ​17.721 ​   4.963   ​0.027 ​  ​0.008 ​  ​0.2293
 08      2.00   ​1.90 ​ 35920   ​4046 ​   8.88  81.18       ​0.1 ​    ​0.0 ​  ​41.435 ​  ​43.993 ​  ​14.417 ​ -0.132 ​ -0.016 ​  ​N/​A</​code>​ 08      2.00   ​1.90 ​ 35920   ​4046 ​   8.88  81.18       ​0.1 ​    ​0.0 ​  ​41.435 ​  ​43.993 ​  ​14.417 ​ -0.132 ​ -0.016 ​  ​N/​A</​code>​
 +
 +===== Contact =====
 +
 +In case of any questions or problems, please do not hesitate and write us: [[martin.maly@fjfi.cvut.cz]].
 +
 +===== Further reading =====
 +
 +  * [[https://​doi.org/​10.1107/​S2052252520005916|Paired refinement under the control of PAIREF. M. Maly, K. Diederichs, J. Dohnalek, P. Kolenko (2020) IUCrJ 7]] 
 +  * More information about //PAIREF// settings and possibilities are explained in the [[https://​pairef.fjfi.cvut.cz/​docs/​|documentation]].
 +
 +  * Linking crystallographic model and data quality. P.A. Karplus & K. Diederichs (2012) Science 336:​1030–3
 +  * Assessing and maximizing data quality in macromolecular crystallography. P.A. Karplus & K. Diederichs (2015) Cur. Op. in Str. Biology 34:60–68
 +  * Better models by discarding data? P.A. Karplus & K. Diederichs (2013) Acta Cryst. D59:​1215–1222
 +