| Quick navigation: | Home | Site Map || References | Biography || Copyright | Other copyright | Contact us | | |
|
|
Re: [ccp4bb] xprep vs shelxc |
|
CCP4bb navigationCCP4bb <-- 2008 <-- February 2008 <-- 13 February 2008Subject: Re: xprep vs shelxc From: Bram Schierbeek bram {- dot -} schierbeek {- at -} BRUKER-AXS {- dot -} NL Date: 2008-02-13 Unfortunately your statement is not true. The XPREP program was written by George Sheldrick over many years and it is proprietary software distributed by Bruker AXS. We unbundled it from our complete SHELXTL structure solution and refinement package, specifically also to serve macromolecular crystallography groups such as those reading this bulletin board. We have a demo version, which groups can try out, academics or industrials, which expires by the end of each year. Anyone can request a demo version by sending an email to demolicense@rt.bruker-axs.nl. If all is well, you should get this demo version once and not more. If you did get it more then once, Tim, we did not do our administration right and you were lucky, or it may be because you have changed labs every year. If people find the software useful they can buy a perpetual license from Bruker AXS for a moderate price. Alternatively they can buy an X-ray diffraction system and get the software for free. As far as the differences between SHELXC and XPREP: On the SHELX website it says: "SHELXC is much less versatile than the Bruker AXS XPREP program for macromolecular phasing, but if you are sure of the space group and there are no problems with the indexing or twinning and the f and f" parts of the scattering factors do not need to be refined, SHELXC should be adequate. SHELXC can read either HKL2000 .sca files or SHELX .hkl files." Xprep has many more possibilities then SHELXC: It can search for higher symmetry in datasets, determine space groups, it has tests for merohedral twinning, reciprocal lattice displays, unit cell transformations and can calculate Self-Rotation functions. The results for anomalous phasing from XPREP look better then those from SHELXC at first sight, but I have not done a rigorous study into this matter. Best wishes, Bram -- ---------------------------------------------------------------------------- Bram Schierbeek Application Scientist Structural Biology Solutions Bruker AXS BV Oostsingel 209,P.O.Box 811 2600 AV Delft, the Netherlands T: +31 (0)152 152 508 F: +31 (0)152 152 599 E: bram.schierbeek@bruker-axs.nl W: www.bruker-axs.com ---------------------------------------------------------------------------- Tim Gruene wrote: > xprep is free to academics. Since your signature says you work at the > University of Helsinki, you would only need to send an informal email > to bruker (you could try their contact form > http://www.bruker-axs.com/contact.html?&L=http%3A%2F%2Fhome.arcor.de%2Fjohnwayne92%2Finc.php > > ) in order to receive a binary. You do have to repeat this every year, > but I think this is a bearable burden. > > As far as the differences between shelxc and xprep are concerned: > shelxc is meant to be a non-interactive basic version of xprep so that > it could be called from other programs. It's data preparation should > be the same as in xprep and if it really did worse than xprep, I am > sure that the improvement from xprep would find its way into shelxc in > very little time. > > We use hkl2map (from Thomas Schneider) routinely for phasing purposes, > and since hkl2map calls shelxc rather than xprep, I cannot confirm > that xprep prepares the data in a better way than shelxc. > > Sincerely, Tim > > -- > Tim Gruene > Institut fuer anorganische Chemie > Tammannstr. 4 > D-37077 Goettingen > > GPG Key ID = A46BEE1A > > > On Wed, 13 Feb 2008, Tommi Kajander wrote: > >> Dear All, >> >> A very simple stupid question: is it worth while getting xprep >> instead of shelxc to do the same job? i realize xprep does a lot of >> other things, but also seem to get the idea from some places that >> it does a better job than shelxc at preparing data from shelxd, or is >> there >> any difference (getting xprep will cost some money so i would like to >> know >> where the difference lies if there is any significant difference??) >> >> Thanks for advice, >> Tommi >> >> >> -- >> Tommi Kajander, Ph.D. >> Macromolecular X-ray Crystallography >> Research Program in Structural Biology and Biophysics >> Institute of Biotechnology >> P.O. Box 65 (Street address: Viikinkaari 1, 4th floor) >> University of Helsinki >> FIN-00014 Helsinki, Finland >> Tel. +358-9-191 58903 >> Fax +358-9-191 59940 >> CCP4bb navigationCCP4bb <-- 2008 <-- February 2008 <-- 13 February 2008 |
| ProteinCrystallography.org: Copyright 2006-2008 by Quid United Ltd |