SHELX C/D/E: Difference between revisions

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SHELXC, SHELXD and SHELXE are stand-alone executables that do not require environment variables or parameter files etc., so all that is needed to install them is to put them in a directory that is in the ‘path’ (e.g. /usr/local/bin or ~/bin under Linux). There is a detailed description of these programs in the paper: <i>"Experimental phasing with SHELXC/D/E: combining chain tracing with density modification"</i>. Sheldrick, G.M. (2010). <i>Acta Cryst.</i> <b>D66</b>, 479-485. It is  
SHELXC, SHELXD and SHELXE are stand-alone executables that do not require environment variables or parameter files etc., so all that is needed to install them is to put them in a directory that is in the ‘path’ (e.g. /usr/local/bin or ~/bin under Linux). There is a detailed description of these programs in the paper: <i>"Experimental phasing with SHELXC/D/E: combining chain tracing with density modification"</i>. Sheldrick, G.M. (2010). <i>Acta Cryst.</i> <b>D66</b>, 479-485. It is  
available as "Open Access" at http://dx.doi.org/10.1107/S0907444909038360 and should be cited whenever these programs are used.
available as "Open Access" at http://dx.doi.org/10.1107/S0907444909038360 and should be cited whenever these programs are used.
[[hkl2map]] is a graphical user interface that makes it easy to use these programs.
[[xds:xdsgui|XDSGUI]] is a graphical user interface for XDS that also makes it easy to use these programs.




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  -z - substructure optimization, number of atoms not limited [off]
  -z - substructure optimization, number of atoms not limited [off]
  -ZX - maximum shift in Ang. from initial position for -O [-Z1.0]
  -ZX - maximum shift in Ang. from initial position for -O [-Z1.0]
Meaning of additional output when using the -x option:
MPE and wMPE are given as two numbers, the one after the '/' is for centric reflections only.
The first nine numbers in the row after locating a strand or in the 'Global chain diagnostics' are the percentages of CA within 0-0.1, 0.1-0.2, 0.2-0.3Å etc from the nearest CA in the reference structure. The tenth number is the percentage further than 0.9Å from the nearest CA.
The next number is 100 times the number of CA found divided by the number expected for the whole structure. The last number is the mean distance of a CA atom from the nearest CA in the reference structure, whereby distances greater than 2.5Å are replaced by 2.5. One should always look at the second number from the right; for a good trace it should be as low as possible. If you are expanding from a MR solution the program also tells you the percentages of starting atoms retained.


=== Phasing and density modification ===
=== Phasing and density modification ===
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for a solved structure (25 to 50%). The solution with the best CC is
for a solved structure (25 to 50%). The solution with the best CC is
written to name.pdb and its phases to name.phs for input to e.g. Coot.
written to name.pdb and its phases to name.phs for input to e.g. Coot.
=== How to tell SHELXE about NCS in a molecular replacement solution PDB file ===
(communicated by Isabel Uson) Insert a line
REMARK 299 NCS GROUP BEGIN
before the ATOM (or HETATM) lines of each NCS group (e.g. chain), and insert the line
REMARK 299 NCS GROUP END
after the last of these. The -n option is not needed then. The output of SHELXE should tell you about the fact that it understood the NCS specification.


== RIP with SHELXC/D/E ==
== RIP with SHELXC/D/E ==
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==  SAD/MAD with automatic backbone building ==
==  SAD/MAD with automatic backbone building ==


  shelxe.beta exp1 exp1_fa -a -q -h -s0.6 -m20 -b
  shelxe exp1 exp1_fa -a -q -h -s0.6 -m20 -b


will use exp1.hkl, exp1_fa.hkl, exp1.ins (as above) and will try 3 cycles of backbone building.
will use exp1.hkl, exp1_fa.hkl, exp1.ins (as above) and will try 3 cycles of backbone building.
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== Obtaining the SHELX programs ==
== Obtaining the SHELX programs ==


SHELXC/D/E and test data may be downloaded from the SHELX fileserver (shelx97 directory). The application form should be printed out from http://shelx.uni-ac.gwdg.de/SHELX/ This form should be completed and faxed to +49-551-3922582.  Downloading instructions will then be emailed to the address given on the form, so please write the email address CLEARLY.  The programs are free to academics but a small license fee is required for 'for-profit' use.   
SHELXC/D/E and test data may be downloaded from the [http://shelx.uni-goettingen.de/bin/ SHELX fileserver]. First fill the application form at http://shelx.uni-goettingen.de/register.php Password and downloading instructions will then be emailed to the address given on the form.  The programs are free to academics but a small license fee is required for 'for-profit' use.   


Beta-test versions are also available from time to time. They are announced by George Sheldrick and are available from the beta-test directory. The username and password for accessing these may be obtained from GS.
Beta-test versions are also available from time to time. They are announced by George Sheldrick and are available from the beta-test directory. The username and password for accessing these may be obtained from GS.


The data merging and internal correlation coefficient as a function of resolution have been fine-tuned in the beta-test SHELXC (available since Aug 19, 2011). The changes only apply when unmerged data are read in and should improve very weak noisy anomalous data.
[[hkl2map]] can be downloaded from a website at EMBL Hamburg.


== References ==
== References ==
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If these programs prove useful, you may wish to cite (and read!):<br>
If these programs prove useful, you may wish to cite (and read!):<br>


Sheldrick, G.M. (2008). "A short history of SHELX", ''Acta Crystallogr''. '''D64''', 112-122 [''Standard reference for all SHELX... programs''].<br>
[http://scripts.iucr.org/cgi-bin/paper?sc5010 Sheldrick, G.M. (2008). "A short history of SHELX", ''Acta Crystallogr''. '''D64''', 112-122] [''Standard reference for all SHELX* programs''].<br>


Sheldrick, G.M., Hauptman, H.A., Weeks, C.M., Miller, R. & Usón, I. (2001). "Ab initio phasing". In ''International Tables for Crystallography'', Vol. F, Eds. Rossmann, M.G. & Arnold, E., IUCr and Kluwer Academic Publishers, Dordrecht pp. 333-351 [''Full background to the dual-space recycling used in SHELXD''].<br>
Sheldrick, G.M., Hauptman, H.A., Weeks, C.M., Miller, R. & Usón, I. (2001). "Ab initio phasing". In ''International Tables for Crystallography'', Vol. F, Eds. Rossmann, M.G. & Arnold, E., IUCr and Kluwer Academic Publishers, Dordrecht pp. 333-351 [''Full background to the dual-space recycling used in SHELXD''].<br>
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Uson, I., Stevenson, C.E.M., Lawson, D.M. & Sheldrick, G.M. (2007). "Structure determination of the O-methyltransferase NovP using the `free lunch algorithm' as implemented in SHELXE", ''Acta Crystallogr''. '''D63''', 1069-1074 [''Implementation of the FLA in SHELXE''].<br>
Uson, I., Stevenson, C.E.M., Lawson, D.M. & Sheldrick, G.M. (2007). "Structure determination of the O-methyltransferase NovP using the `free lunch algorithm' as implemented in SHELXE", ''Acta Crystallogr''. '''D63''', 1069-1074 [''Implementation of the FLA in SHELXE''].<br>


Sheldrick, G.M. (2010). "Experimental phasing with SHELXC/D/E: combining chain tracing with density modification", ''Acta Cryst'' '''D66''', 479-485. "Open Access" at http://dx.doi.org/10.1107/S0907444909038360
[http://dx.doi.org/10.1107/S0907444909038360 Sheldrick, G.M. (2010). "Experimental phasing with SHELXC/D/E: combining chain tracing with density modification", ''Acta Cryst'' '''D66''', 479-485.]


[https://doi.org/10.1107/S0907444913027534 A. Thorn and Sheldrick, G.M. (2013) Extending molecular-replacement solutions with SHELXE. ''Acta Cryst'' '''D69''', 2251-2256.]
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See also the SHELX homepage at: http://shelx.uni-ac.gwdg.de/SHELX/
See also the [http://shelx.uni-goettingen.de/ SHELX homepage]
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